has difficulty an effect on AI decision making?

[spotlight2001]

On selecting campaign difficulty I can see buffs, ...

I have just startet with "general" ... and it seemed like AI units made weird suicide moves. At least I dont remember it from former "generalissimus" difficulty.

Is it just the visible buffs? Or does AI behave "smarter" on higher difficulty?

[Bee1976]

AFAIK AI calculates the combats and based on the results AI decides to attack or to not attack. If you raise the difficulty, AI hits better. That can lead to attacks the AI wont do on lower difficulties because it can now do casualties to you.

But there are many ways to alter the AI behavior. The agression level for example. The randomness selection and so on. On most maps and in most missions the AI wouldnt attack, if it can´t harm you.
And you can play around that and change AI behavior, by difficulty, by positive and negative traits like the enttrenchment one or the one that limits your ammunition ressuply or raises the cost of 1 shot and so on.

If you want a ridicolously brutal AI, select "slow reaction" trait, the one that makes your units not fighting back. Everything will attack you in the most brutal and ruthless manner (but you can play around that aswell with tons of support units)

[DefiantXYX]

I would say no.
Afaik these settings only change how much prestige you get and on hardest difficulty AI gets some extra base accuracy.
It might look like it not so smart on lower difficulty.

Lets say on general an unit can kill 1 HP by losing 3 HP. AI will attack if 1 HP is worse more prestige than the 3 HP who might get lost. (203cm Art. vs cheap infantry for example).
Since the outcome is random (depending again on your settings) its more likely, that the AI doesnt kill a single unit.
Same fight on generalismus, AI will kill 2 HP by losing 3 (20% more base accuracy), so its unlikely, that it wont kill a thing.

But basically AI is very stupid, and only calculating prestige.

[Tassadar]

I have just startet with "general" ... and it seemed like AI units made weird suicide moves. At least I dont remember it from former "generalissimus" difficulty.

Generalissimus should in fact make the AI more aggressive. The extra accuracy it gets makes it see better combat predictions and attack more often. It interesting you are observing it on lower difficulty instead. It can be other due to some traits (Terrain Expert helps with aggression for example) or a change in tactics you are using, possibly also just the case of scenarios as people mentioned. The AI aggressiveness level is different per map and often per unit groups, so it can lead to interesting dynamics even with how simple the AI is.