Elite AI sometimes really likes to attack, even among each other.

But even "normal AI" attacks occasionally "by mistake" (or better sayed because the AI is stupid).
At least it used to be that way as I observed it several times.

Possibility exists for example if AI units have moved to provinces where they have RoW and due to rebellion or conquest by third party they suddenly stand in "no man's land".

Or eg AI units with already active "timer" for the next order/s (means an ongoing, but not yet completed command for movement or attack) will march through a previously own province which in meantime has rebelled ..
.. if there is no RoW with the new owner it comes to war then.

It's a similar scheme as just like the other way around I think >> If peace is offered to AI, a still running "timer" can lead to counter-attacks of AI before the peace is agreed.

It depends on your popularity that you can find in your profile. If you always declare war nicely to AI before attacking and you do a lot of trading in the market with possible AI then your popularity will be high. If it is low then AI can attack randomly. Usually only AI that you are in war with will attack. Elite AI, well that's another kind of breath.

That's about how it works with elite AI.

That's how it in principle works with normal AI.


Normal AI will NEVER "deliberately" start a war -- however, at certain constellations it can happen "by mistake" ..

.. if a AI unit is in a foreign province where it previously had RoW, but the province now belongs to a nation where the AI has no RoW (Rebellion, Conquest) and the AI unit reaches the province center, or comes in contact with native units, even if the AI unit stands still and the native unit runs towards by marching (not by attacking), in both cases war will triggered in which the AI unit is regarded as the attacker (War, without warning..), since the AI is located unauthorized in a foreign territory (..is the intruder).