Stellaris - v3.4.3 (9d15) - Devastating war AI Bug - Overlord won't lift a finger to save themselves

[Methone]

Description
v3.4.3 (9d15) - Devastating war AI Bug - Overlord won't lift a finger to save themselves

Game Version
v3.4.3 (9d15)

What version do you use?
Steam

What expansions do you have installed?
Synthetic Dawn, Utopia, Leviathans Story Pack, Apocalypse, Megacorp, Distant Stars, Ancient Relics, Lithoids, Federations, Aquatics

Do you have mods enabled?
No

Please explain your issue is in as much detail as possible.
I am the Prospectorium of a Driven Assimilator. The Assimilator is currently at war with a Subterranean Slaving Despot and has handily dismantled them, but is taking ages to bombard their worlds and invade them.

At this point, the Peaceful Traders bordering the Assimilator declared war on it - and by extension, me. Their fleets quickly surged into the Assimilator's core territory. There was also technically a Ruthless Megacorp invited to attack the Assimilator, but they didn't have border access.

Now, the Assimilator has more than enough fleet power to crush this Peaceful Trader. However, they don't move their fleets off from bombarding the Despot's worlds. This leaves me to do all the heavy lifting myself - and considering that this Peaceful Trader's fleet power is OVERWHELMING to me, this is... a bit stressful.

Steps to reproduce the issue.
Be the Prospectorium of an Assimilator. Have the Assimilator declare war on a 3rd party and start bombarding their worlds long-term - having the 3rd party be Subterranean likely helps with this. Have a 4th party declare war on the Assimilator. Watch as the Assimilator ignores the threat in favor of bombarding the worlds.

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[pmchem]

someone else reported in another bug that AI is unable to stop bombarding until the bombard-planets are invaded

this seems problematic as your example shows

 

[SirBlackAxe]

As @pmchem said, the AI seems to ridiculously overprioritize planetary bombardment. I think you should be able to get around this situation and salvage your game if you can build armies to invade the planets the AI is bombarding yourself, which will free up its fleets to perform other tasks.

 

[Methone]

As @pmchem said, the AI seems to ridiculously overprioritize planetary bombardment. I think you should be able to get around this situation and salvage your game if you can build armies to invade the planets the AI is bombarding yourself, which will free up its fleets to perform other tasks.

I can't. I'm not technically at war with the nation the AI is bombarding, and I have limited diplomacy as per the agreement.

 

[Offe]

Unfortunately this is not an trivial bug to fix as it falls entirely under poor AI decision making, this problem is probably more noticeable now compared to before as the AI will generally have fewer bigger fleets in the new update, making it more important that they use all of them in a good way.

This issue has been reported several times as well for specifically fallen empires where they do not defend their home worlds but rather go somewhere to bombard a useless planet.

3.4 Came with a lot of bugfixes for AI fleet behavior but their overall decision making still need a lot of improvement