[2.3.2] Defender/attacker flips during combat

[Jorlem]

I'm fairly sure this has been reported on prior patches, but I wanted to make sure it was known that this can still happen in 2.3.2.

I've seen this happen twice recently, once in a MP game, and again a few hours ago. What happens is that, during combat, the attacking and defending armies swap places on the battle window, and whoever was initially attacking gets the defensive bonus, and whoever was initially defending gets whatever penalty the attacker might have had. I noticed this bug when my army suddenly gained the Major River Crossing penalty midway through the battle, even though my army never actually crossed the river.

I think this might be triggered by reinforcements arriving to the battle. In the one with the Major River Crossing I mentioned, both I and my enemy had several armies entering the battle after the combat had started, and the AI's armies were all entering the battle by crossing the river. Unfortunately, I wasn't paying extremely close attention to the reinforcements, but maybe we both had reinforcements arrive on the same day, and something weird happened?

 

[Dracko81]

It is caused because an allie that was called into the war - who was leading the army - died, resulting in his troops and all others from leaving the battle. This places those troops as stationary in the province, and moves your troops into the position afterwards, resulting in a new battle taking place with you as the attacker.

 

[Jorlem]

Then why did I get the major river crossing penalty, if it was a new battle with both armies starting in the same province?

 

[Dracko81]

Pretty sure it is because in these cases, where one army appears to teleport onto another, all available penalties in that province are applied.

 

[NewbieOne]

I can't be sure of this, but perhaps if you watch the entire sequence again in slo-mo, you may be able to find some clues.

In a situation in which, let's say, for example:

On 1 March your ally's army moved into the province.
On 3 March your ally was attacked by the enemy.
On 5 March your army moved in and joined on the defence side.
On 7 March your ally died, and his units stopped being hostile to the enemy or allied to you.

In the above situation an argument could be made that (1) you, de facto, had been attacking the enemy to help your ally defend, so now you're only attacking.

On the other hand, it's equally possible (or perhaps even more probable) that (2) you joined your ally's ranks, which would have placed you in the defending position along with your ally. With your ally leaving, you would become, or rather remain, the sole defender, with the enemy remaining the attacking/active party who is doing the advancing and pushing.

I'm more inclined to see it the #2 way, and it doesn't make sense to always invert your positions just because your army arrived later in the same province, some time in the past. Sometimes, arguably, it does — i.e. whenever your joining of the defence can be construed as de fact attacking the enemy from the rear or side without joining your ally's battle positions.

 

[Jorlem]

Unfortunately, I don't have a save to watch the battle again, but I do know that the only AIs on my side that were involved in that battle arrived after the battle had already started.

 

[NewbieOne]

Unfortunately, I don't have a save to watch the battle again, but I do know that the only AIs on my side that were involved in that battle arrived after the battle had already started.

I recall at least one similar situation, and I suspect it may have something to do with move orders/arrival order, making a different army start a new battle — but I can't exclude that a fluid attacker-to-defender flip occurred, because I too wasn't watching too closely on low speed.

Perhaps try and recall some of the surrounding circumstances and slow down next time you have a similar situation with large enough armies involved for the battle to last a longer while and potentially spawn this issue?

 

[PeterSkager]

I've been trying to create a repro for this myself the past few days, but I'll make the devs aware of it and see if they have any input this Tried to reproduce it with having an allie be the defender and then jumping into the battle and then killing my ally to see what would happen, but I stayed as the defender.

 

[Jorlem]

I'm fairly sure both the AI and myself had a number of armies streaming into the battle at the time it flipped. It wasn't just one big army against another.

Edit:
Perhaps the army I had in the province initially was completely wiped out, and all that were left were the reinforcements that had already arrived and were arriving? I do know that it didn't end the battle, as I only got a single results screen, but maybe that did something?

 

[PeterSkager]

Hm.. Interesting indeed. I migth run a few MP tests to see if it uncovers anything.