Friendly ally becoming rival and breaking alliance

  • We have updated our Community Code of Conduct. Please read through the new rules for the forum that are an integral part of Paradox Interactive’s User Agreement.

jonman122

Second Lieutenant
65 Badges
Jul 23, 2013
197
3
  • Crusader Kings II
  • Heir to the Throne
  • Europa Universalis IV
  • Divine Wind
  • Europa Universalis III Complete
  • Hearts of Iron IV Sign-up
  • Cities: Skylines Deluxe Edition
  • Europa Universalis IV: El Dorado
  • Mount & Blade: Warband
  • Pillars of Eternity
  • Europa Universalis IV: Common Sense
  • Europa Universalis IV: Cossacks
  • Europa Universalis IV: Mare Nostrum
  • Stellaris
  • Stellaris: Necroids
  • Stellaris: Galaxy Edition
  • Stellaris: Galaxy Edition
  • Europa Universalis IV: Third Rome
  • Stellaris Sign-up
  • Cities in Motion 2
  • Surviving Mars
  • BATTLETECH
  • Hearts of Iron IV: Cadet
  • Europa Universalis IV: Rights of Man
  • Stellaris: Digital Anniversary Edition
  • Stellaris: Leviathans Story Pack
  • Stellaris - Path to Destruction bundle
  • Europa Universalis IV: Mandate of Heaven
  • Europa Universalis IV: Conquest of Paradise
  • Crusader Kings II: Charlemagne
  • Crusader Kings II: Legacy of Rome
  • Crusader Kings II: The Old Gods
  • Crusader Kings II: Rajas of India
  • Crusader Kings II: The Republic
  • Crusader Kings II: Sons of Abraham
  • Crusader Kings II: Sunset Invasion
  • Crusader Kings II: Sword of Islam
  • Europa Universalis III
  • Europa Universalis III: Chronicles
  • Europa Universalis IV: Art of War
  • Cities: Skylines
  • Europa Universalis IV: Wealth of Nations
  • Europa Universalis IV: Call to arms event
  • Europa Universalis III Complete
  • Magicka
  • Europa Universalis III Complete
  • Europa Universalis IV: Res Publica
  • Victoria: Revolutions
  • Victoria 2
  • Victoria 2: A House Divided
This is a fair point, but RMs do break on monarch death now (always? often? but it does happen, at any rate). But yes, the comparison with coalitions is apt. Both mechanics are like bulls in china shops.

I don't like whatever they've done to royal marriages, I have to renew them so often now it's ridiculous.
 

LarryLeica

Major Major
90 Badges
Mar 29, 2011
1.970
88
  • Stellaris: Ancient Relics
  • Stellaris: Lithoids
  • Stellaris: Federations
  • Crusader Kings III
  • Stellaris: Distant Stars
  • Crusader Kings III: Royal Edition
  • Hearts of Iron IV: Expansion Pass
  • Battle for Bosporus
  • Europa Universalis IV
  • Stellaris: Necroids
  • Europa Universalis IV: Cossacks
  • Europa Universalis IV: Res Publica
  • Semper Fi
  • Stellaris - Path to Destruction bundle
  • Crusader Kings II: Monks and Mystics
  • Europa Universalis IV: Pre-order
  • Europa Universalis IV: Third Rome
  • Pillars of Eternity
  • Cities: Skylines - After Dark
  • Victoria 2: A House Divided
  • Stellaris: Synthetic Dawn
  • Cities: Skylines - Snowfall
  • Europa Universalis IV: Mare Nostrum
  • Stellaris: Galaxy Edition
  • Stellaris: Galaxy Edition
  • Crusader Kings II
  • Crusader Kings II: Jade Dragon
  • Hearts of Iron III: Their Finest Hour
  • Crusader Kings II: Charlemagne
  • Crusader Kings II: Legacy of Rome
  • Crusader Kings II: The Old Gods
  • Crusader Kings II: Rajas of India
  • Crusader Kings II: The Republic
  • Crusader Kings II: Sons of Abraham
  • Crusader Kings II: Sunset Invasion
  • Crusader Kings II: Sword of Islam
  • Europa Universalis IV: Art of War
  • Europa Universalis IV: Conquest of Paradise
  • Europa Universalis IV: Wealth of Nations
  • Europa Universalis IV: Call to arms event
  • For the Motherland
  • Hearts of Iron III
  • March of the Eagles
  • Surviving Mars
  • Hearts of Iron IV: Death or Dishonor
  • BATTLETECH
  • Cities: Skylines - Green Cities
  • Steel Division: Normandy 44 Deluxe Edition
  • Europa Universalis IV: Mandate of Heaven
  • Hearts of Iron IV: Cadet
In my experience the weird flip-flop behaviour tends to happen after one of you has finished a particularly tough war creating a significant power imbalance because of depleted manpower reserves and (possibly) low troop levels. I think it is odd that the AI reacts so dramatically and so suddenly to a short term shift in the balance of power and would prefer to see it take a little longer to assess the situation properly.

I think you might be onto something there. When the 'ally' enters this evaluation state, there should be some sort of cooldown to see if circumstances change, say 6 months...

I've come to find that this argument has absolutely no merit. In a game where as england I took Judea for a mission and saved Byzantium from utter destruction while giving them back all of their cores (as an ally) in a war against the Ottomans, they suddenly considered themselves to be on par with me and I was immediately rivaled and alliances broken, while still being at 200 relations due to the provinces given in peace. They then died horribly to the Ottomans and after being nearly completely annexed, they wanted an alliance again. It's actually really dumb.

Yes, that sort of situation is rather silly, but it doesn't happen that often, just that when it does, it's shows up all the flaws in the system as it stands.
 

Apple.the.Great

Recruit
Feb 23, 2014
3
0
It always annoys me to no end when as England, Portugal (England's oldest ally in the real world) breaks off its alliance with me and goes over to Castille and selects me as a rival. Surely Portual and Castille/Spain are more natural rivals than Portugal and England?
 

knoddy

Lt. General
2 Badges
Jul 8, 2008
1.557
295
  • Imperator: Rome Sign Up
  • Europa Universalis IV
I agree with what others have posted, it is ridiculus that an ally who you have 200+ relations with, can just instalty Rival you and break your alliance. Again as others have said I have no issue with the relationship gradually getting worse if there is a reason, but it should still be maintainable.

In my current Najd game, I gave up all other allies, to keep the Ottomans, together we rolled the QQ guys and the Mamlukes in many wars. they trust me implicitly. I took no land in any of those wars, I let them have their strategic goals every time. I also annoyed Persia and the Timurids both of whom are large bordering countries, to stay allied to them. then one day BAM, alliance broken, rivaled, negative relations (but they still trust me implicitly lol) and now Im surrounded by 3 Large rivals and very scared.

I think the reason they are pissed with me, is because they are getting no trade flow to Alexandria or on from Basra. But still.

My suggestion would be to introduce a ticking score of negative opinion that gives you some indication of them being upset. "strategic interests" -15 +1 every year or something. At least this means, I have some warning, that im about to be up the creek without a paddle. and I can start looking for another big ally.
 

laijka

Captain
115 Badges
May 29, 2011
425
42
  • Stellaris
  • Hearts of Iron III Collection
  • Heir to the Throne
  • King Arthur II
  • Leviathan: Warships
  • Magicka
  • March of the Eagles
  • Cities: Skylines - Natural Disasters
  • Europa Universalis IV: Res Publica
  • Victoria: Revolutions
  • Sengoku
  • Sword of the Stars
  • Cities in Motion
  • The Showdown Effect
  • Victoria 2
  • Victoria 2: A House Divided
  • Victoria 2: Heart of Darkness
  • Europa Universalis IV: Third Rome
  • Cities: Skylines - Snowfall
  • Europa Universalis IV: Pre-order
  • Europa Universalis IV: Cossacks
  • Pillars of Eternity
  • Cities: Skylines - After Dark
  • Crusader Kings II: Sunset Invasion
  • Hearts of Iron II: Armageddon
  • Crusader Kings II
  • Crusader Kings II: Charlemagne
  • Crusader Kings II: Legacy of Rome
  • Crusader Kings II: The Old Gods
  • Crusader Kings II: Rajas of India
  • Crusader Kings II: The Republic
  • Crusader Kings II: Sons of Abraham
  • Hearts of Iron III: Their Finest Hour
  • Crusader Kings II: Sword of Islam
  • Deus Vult
  • Dungeonland
  • Europa Universalis III
  • Europa Universalis III: Chronicles
  • Europa Universalis III Complete
  • Divine Wind
  • Europa Universalis IV
  • Europa Universalis IV: Art of War
  • Europa Universalis IV: Conquest of Paradise
  • Europa Universalis IV: Wealth of Nations
  • Europa Universalis IV: Call to arms event
  • Warlock: Master of the Arcane
  • Empire of Sin
  • Mount & Blade: Warband
  • Mount & Blade: With Fire and Sword
  • Crusader Kings II: Way of Life
It always annoys me to no end when as England, Portugal (England's oldest ally in the real world) breaks off its alliance with me and goes over to Castille and selects me as a rival. Surely Portual and Castille/Spain are more natural rivals than Portugal and England?

I don't know, I can see reasons for the switch. As Portugal you either have to ally other big powers and hope they can keep Castille/Spain in check or cozy up with Castille/Spain directly. Adding to that it's very likely that you are competing in some trade node and maybe even competing in the same colony regions and it's not very far fetched that they would switch over.
 

Yxklyx

Field Marshal
47 Badges
Jan 30, 2011
4.712
720
  • Crusader Kings II
  • Europa Universalis III Complete
  • Victoria 2: A House Divided
  • Cities: Skylines
  • Crusader Kings II: Monks and Mystics
  • Europa Universalis IV: Common Sense
  • Crusader Kings II: Horse Lords
  • Crusader Kings II: Conclave
  • Stellaris
  • Stellaris: Galaxy Edition
  • Crusader Kings II: Reapers Due
  • Europa Universalis IV: Rights of Man
  • Crusader Kings II: Way of Life
  • Europa Universalis IV: Mandate of Heaven
  • Europa Universalis IV: Cradle of Civilization
  • Europa Universalis IV: Rule Britannia
  • Europa Universalis IV: Dharma
  • Crusader Kings II: Holy Fury
  • Europa Universalis IV: Golden Century
  • Prison Architect
  • Age of Wonders: Planetfall
  • Europa Universalis 4: Emperor
  • 500k Club
  • Victoria 2: Heart of Darkness
  • Victoria 2
  • Europa Universalis IV: El Dorado
  • Europa Universalis III Complete
  • Europa Universalis III Complete
  • Europa Universalis IV
  • Crusader Kings II: Charlemagne
  • Crusader Kings II: Legacy of Rome
  • Crusader Kings II: The Old Gods
  • Crusader Kings II: Rajas of India
  • Crusader Kings II: The Republic
  • Crusader Kings II: Sons of Abraham
  • Crusader Kings II: Sword of Islam
  • Crusader Kings II: Jade Dragon
  • Europa Universalis III
  • Europa Universalis IV: Third Rome
  • Europa Universalis IV: Art of War
  • Europa Universalis IV: Conquest of Paradise
  • Europa Universalis IV: Wealth of Nations
  • Stellaris: Galaxy Edition
  • Europa Universalis IV: Mare Nostrum
  • Europa Universalis IV: Res Publica
  • Europa Universalis IV: Cossacks
  • Cities: Skylines - After Dark
allies breaking alliance and rival you is sort of ok, but twice a nation allied to me suddenly rivaled me and in two days turned back to friendly. that is just ridicules

I've done that myself when I wanted to fabricate a claim on an ally. They actually don't seem to mind being temporarily rivaled.
 

wetblowdryer

Colonel
101 Badges
Nov 27, 2013
1.153
1.571
  • Rome Gold
  • Hearts of Iron III: Their Finest Hour
  • Hearts of Iron III
  • For the Motherland
  • Europa Universalis IV: Wealth of Nations
  • Europa Universalis IV: Conquest of Paradise
  • Magicka
  • Europa Universalis IV: Res Publica
  • Victoria: Revolutions
  • Darkest Hour
  • Sengoku
  • Victoria 2: A House Divided
  • Victoria 2: Heart of Darkness
  • Rome: Vae Victis
  • Crusader Kings II
  • Cities: Skylines
  • Europa Universalis IV: El Dorado
  • Europa Universalis III: Collection
  • Europa Universalis IV: Pre-order
  • Hearts of Iron IV: No Step Back
  • Mount & Blade: Warband
  • Mount & Blade: With Fire and Sword
  • Crusader Kings II: Way of Life
  • Pillars of Eternity
  • Europa Universalis IV: Common Sense
  • Crusader Kings II: Horse Lords
  • Cities: Skylines - After Dark
  • Europa Universalis IV: Cossacks
  • Crusader Kings II: Conclave
  • Cities: Skylines - Snowfall
  • Europa Universalis IV: Mare Nostrum
  • Stellaris
  • Hearts of Iron IV Sign-up
  • Europa Universalis III
  • Crusader Kings II: Charlemagne
  • Crusader Kings II: Legacy of Rome
  • Crusader Kings II: The Old Gods
  • Crusader Kings II: Rajas of India
  • Crusader Kings II: The Republic
  • Crusader Kings II: Sons of Abraham
  • Crusader Kings II: Sunset Invasion
  • Crusader Kings II: Sword of Islam
  • Warlock 2: The Exiled
  • Divine Wind
  • Europa Universalis IV
  • Europa Universalis IV: Art of War
  • Europa Universalis IV: Call to arms event
  • Hearts of Iron III Collection
  • Heir to the Throne
  • Semper Fi
It always annoys me to no end when as England, Portugal (England's oldest ally in the real world) breaks off its alliance with me and goes over to Castille and selects me as a rival. Surely Portual and Castille/Spain are more natural rivals than Portugal and England?

To me, (being a human) I think that allying with Castile is better than allying with useless England due to location and Castile normally having larger and better armies.
 

TheMeInTeam

Field Marshal
54 Badges
Dec 27, 2013
30.274
18.949
  • Age of Wonders III
  • Crusader Kings II: Conclave
  • Hearts of Iron IV: No Step Back
  • Stellaris
  • Hearts of Iron IV: Cadet
  • Crusader Kings II: Reapers Due
  • Europa Universalis IV: Rights of Man
  • Hearts of Iron IV: Together for Victory
  • Crusader Kings II: Monks and Mystics
  • Europa Universalis IV: Mandate of Heaven
  • Europa Universalis 4: Emperor
  • Hearts of Iron IV: Death or Dishonor
  • Stellaris: Synthetic Dawn
  • Europa Universalis IV: Cossacks
  • Europa Universalis IV: Cradle of Civilization
  • Battle for Bosporus
  • Hearts of Iron IV: Expansion Pass
  • Europa Universalis IV: Rule Britannia
  • Europa Universalis IV: Dharma
  • Crusader Kings II: Holy Fury
  • Europa Universalis IV: Golden Century
  • Hearts of Iron IV: Expansion Pass
  • Prison Architect
  • Hearts of Iron IV: La Resistance
  • Crusader Kings III
  • Crusader Kings II: Horse Lords
  • Europa Universalis IV: Common Sense
  • Magicka 2
  • Crusader Kings II: Way of Life
  • Europa Universalis IV: El Dorado
  • Victoria 2
  • Europa Universalis IV
  • Crusader Kings II: Charlemagne
  • Crusader Kings II
  • Crusader Kings II: Legacy of Rome
  • Crusader Kings II: The Old Gods
  • Crusader Kings II: Rajas of India
  • Crusader Kings II: The Republic
  • Crusader Kings II: Sons of Abraham
  • Crusader Kings II: Sunset Invasion
  • Crusader Kings II: Sword of Islam
  • Europa Universalis IV: Art of War
  • Europa Universalis IV: Conquest of Paradise
  • Europa Universalis IV: Wealth of Nations
  • Hearts of Iron III
  • Magicka
  • Europa Universalis IV: Res Publica
  • Stellaris - Path to Destruction bundle
  • Victoria 2: A House Divided
  • Victoria 2: Heart of Darkness
I've had this too, however, I'm not convinced it's actually broken (as some have suggested) more in need of tweaking.

Playing a game as Hungary (I'm a masochist)... I've successfully sustained an alliance with France since the beginning of the game, fought many wars together, and they 'trust Hungary implicitly'. I'd had a similar thing with Muscovy; however, after Poland integrated Lithuania I supported Ukrainian rebels and they won. I guaranteed them, we married, and allied, then Muscovy (now Russia) broke the alliance and rivaled me.

The Muscovy situation is ok, it fits in the sense that here's a newly independent nation that I have supported right on it's borders, it's a threat as they have no idea what my intentions are. However, a year later, they unrival me, and want to be best friends again, they even make an alliance with Ukraine and we all fight together in a war against a newly independent Lithuania. Straight after the war, poof, rivaled again, I took no territory in this war.

I think the bigger issue here is the flip-flopping, why go from implicit trust to rival so quickly?

One thing I have noticed is that I have guaranteed France (so I get called in as they are usually fighting Austria, or Italian states which is good for me), I did not guarantee Muscovy. Am curious if there is some hidden modifier at play here?

The AI has no mechanic for long-range planning + situational alliances, so it uses this rival flip-flop to play its interests. It's not "broken" from a design standpoint per se', but rather just an example of weak AI in an area.

What bothers me is that the AI will too often telegraph its punches, declaring hostility long before it actually engages in hostilities. IMO it should not be breaking alliances and turning hostile/rival unless it fears an attack on the player it can't survive by joining or it *actually* intends to attack the player. If it's just breaking it for #relations or whatever it wouldn't be turning hostile...in theory...but that's fine too.

What isn't fine, IMO, is that they player is forced to be angry over this. You can make temp alliances with other human players, and they happened in reality too. The game even lies and says our opinions are up to us, but in reality they aren't; we can't do this very thing the AI wants, which is to ally it on a sporadic basis. That's nonsense.
 

Paddymorrow@blu

Corporal
62 Badges
Aug 18, 2008
33
5
  • Semper Fi
  • Crusader Kings II: Jade Dragon
  • Crusader Kings II: Monks and Mystics
  • Europa Universalis IV: Mare Nostrum
  • Europa Universalis IV: Pre-order
  • Victoria 2: Heart of Darkness
  • Victoria 2: A House Divided
  • Crusader Kings II
  • Victoria: Revolutions
  • Europa Universalis IV: Res Publica
  • Heir to the Throne
  • Hearts of Iron III: Their Finest Hour
  • Hearts of Iron III
  • For the Motherland
  • Europa Universalis IV: Call to arms event
  • Europa Universalis IV: Conquest of Paradise
  • Crusader Kings II: Charlemagne
  • Crusader Kings II: Legacy of Rome
  • Crusader Kings II: The Old Gods
  • Crusader Kings II: Rajas of India
  • Crusader Kings II: The Republic
  • Crusader Kings II: Sons of Abraham
  • Crusader Kings II: Sword of Islam
  • Europa Universalis III
  • Europa Universalis IV: Wealth of Nations
  • Europa Universalis III Complete
  • Divine Wind
  • Europa Universalis IV: Art of War
  • Europa Universalis III: Chronicles
  • Europa Universalis IV
  • Europa Universalis 4: Emperor
  • Hearts of Iron IV: Death or Dishonor
  • Surviving Mars
  • BATTLETECH
  • Europa Universalis IV: Third Rome
  • Europa Universalis IV: Mandate of Heaven
  • Europa Universalis IV: Rights of Man
  • Crusader Kings II: Reapers Due
  • Hearts of Iron IV: Field Marshal
  • Hearts of Iron IV: Colonel
  • Hearts of Iron IV: Cadet
  • Crusader Kings II: Conclave
  • Europa Universalis IV: Cossacks
  • Crusader Kings II: Horse Lords
  • Europa Universalis IV: Common Sense
  • Crusader Kings II: Way of Life
  • Europa Universalis IV: El Dorado
  • 500k Club
  • Europa Universalis III Complete
  • Victoria 2
Had the same sort of nonsense in my game, playing GB (now 1603) firm allies with Portugal, my king dies and leaves me with a regency council, next day Portugal breaks alliance, sets me up as rival. I now have a -137 opinion score with them....but the real laugh is that "Portugal trusts me utterly" WTF???
 

TheMeInTeam

Field Marshal
54 Badges
Dec 27, 2013
30.274
18.949
  • Age of Wonders III
  • Crusader Kings II: Conclave
  • Hearts of Iron IV: No Step Back
  • Stellaris
  • Hearts of Iron IV: Cadet
  • Crusader Kings II: Reapers Due
  • Europa Universalis IV: Rights of Man
  • Hearts of Iron IV: Together for Victory
  • Crusader Kings II: Monks and Mystics
  • Europa Universalis IV: Mandate of Heaven
  • Europa Universalis 4: Emperor
  • Hearts of Iron IV: Death or Dishonor
  • Stellaris: Synthetic Dawn
  • Europa Universalis IV: Cossacks
  • Europa Universalis IV: Cradle of Civilization
  • Battle for Bosporus
  • Hearts of Iron IV: Expansion Pass
  • Europa Universalis IV: Rule Britannia
  • Europa Universalis IV: Dharma
  • Crusader Kings II: Holy Fury
  • Europa Universalis IV: Golden Century
  • Hearts of Iron IV: Expansion Pass
  • Prison Architect
  • Hearts of Iron IV: La Resistance
  • Crusader Kings III
  • Crusader Kings II: Horse Lords
  • Europa Universalis IV: Common Sense
  • Magicka 2
  • Crusader Kings II: Way of Life
  • Europa Universalis IV: El Dorado
  • Victoria 2
  • Europa Universalis IV
  • Crusader Kings II: Charlemagne
  • Crusader Kings II
  • Crusader Kings II: Legacy of Rome
  • Crusader Kings II: The Old Gods
  • Crusader Kings II: Rajas of India
  • Crusader Kings II: The Republic
  • Crusader Kings II: Sons of Abraham
  • Crusader Kings II: Sunset Invasion
  • Crusader Kings II: Sword of Islam
  • Europa Universalis IV: Art of War
  • Europa Universalis IV: Conquest of Paradise
  • Europa Universalis IV: Wealth of Nations
  • Hearts of Iron III
  • Magicka
  • Europa Universalis IV: Res Publica
  • Stellaris - Path to Destruction bundle
  • Victoria 2: A House Divided
  • Victoria 2: Heart of Darkness
Had the same sort of nonsense in my game, playing GB (now 1603) firm allies with Portugal, my king dies and leaves me with a regency council, next day Portugal breaks alliance, sets me up as rival. I now have a -137 opinion score with them....but the real laugh is that "Portugal trusts me utterly" WTF???

Just because you shouldn't trust them doesn't mean they don't (mistakenly) trust you ;).
 

Yxklyx

Field Marshal
47 Badges
Jan 30, 2011
4.712
720
  • Crusader Kings II
  • Europa Universalis III Complete
  • Victoria 2: A House Divided
  • Cities: Skylines
  • Crusader Kings II: Monks and Mystics
  • Europa Universalis IV: Common Sense
  • Crusader Kings II: Horse Lords
  • Crusader Kings II: Conclave
  • Stellaris
  • Stellaris: Galaxy Edition
  • Crusader Kings II: Reapers Due
  • Europa Universalis IV: Rights of Man
  • Crusader Kings II: Way of Life
  • Europa Universalis IV: Mandate of Heaven
  • Europa Universalis IV: Cradle of Civilization
  • Europa Universalis IV: Rule Britannia
  • Europa Universalis IV: Dharma
  • Crusader Kings II: Holy Fury
  • Europa Universalis IV: Golden Century
  • Prison Architect
  • Age of Wonders: Planetfall
  • Europa Universalis 4: Emperor
  • 500k Club
  • Victoria 2: Heart of Darkness
  • Victoria 2
  • Europa Universalis IV: El Dorado
  • Europa Universalis III Complete
  • Europa Universalis III Complete
  • Europa Universalis IV
  • Crusader Kings II: Charlemagne
  • Crusader Kings II: Legacy of Rome
  • Crusader Kings II: The Old Gods
  • Crusader Kings II: Rajas of India
  • Crusader Kings II: The Republic
  • Crusader Kings II: Sons of Abraham
  • Crusader Kings II: Sword of Islam
  • Crusader Kings II: Jade Dragon
  • Europa Universalis III
  • Europa Universalis IV: Third Rome
  • Europa Universalis IV: Art of War
  • Europa Universalis IV: Conquest of Paradise
  • Europa Universalis IV: Wealth of Nations
  • Stellaris: Galaxy Edition
  • Europa Universalis IV: Mare Nostrum
  • Europa Universalis IV: Res Publica
  • Europa Universalis IV: Cossacks
  • Cities: Skylines - After Dark
Had the same sort of nonsense in my game, playing GB (now 1603) firm allies with Portugal, my king dies and leaves me with a regency council, next day Portugal breaks alliance, sets me up as rival. I now have a -137 opinion score with them....but the real laugh is that "Portugal trusts me utterly" WTF???

Did you recently start trading in a node Portugal is in? Put a merchant there and/or send light ships? That seems to be one cause of this - the AI likes to Embargo and goes to Rival status to do this and it seems to prioritize this over anything else.

I've been allied with France nearly the entire game and recently had a scare. During a war in which we were fighting on the same side (one of the many) his attitude changed to Hostile. So, I started planning for my eventual demise - but then a few months later he's back to Friendly - with the same war still waging.