When an Independent's turn timer hits 10 it goes into Decline. This also opens it up to Assimilation regardless of Patronage levels. I'm guessing this Assimilation option was introduced to give players a "last chance" to nab it if they discovered the Independent too late to do the usual Assimilation via Patronage. But it interacts poorly with simultaneous turns. If another Empire has visibility on an Independent about to go into Decline, they can Assimilate it before the player sees the option on their turn. If you're aware of the situation, you can work around this by selecting the Independent to bring up its menu, clicking End Turn, and immediately clicking Assimilate while the other Empires are acting. This works but it feels very game-y and punishing to me. Players should have time to review the options available to them. Possible solutions...

1) Make the AI delay for a turn before choosing Assimilate

2) Let the player Assimilate at Turn 11 instead of Turn 10

3) Don't allow this special case of Assimilation at all - you either have time to do it the usual way or you can't Assimliate

I prefer #3. If you discover an Independent too late, they just can't be Assimilated. There simply isn't time enough to influence them. Wait out their decline and take their land when they disappear. This seems more historical than the current situation and eliminates special cases.

I agree with #3

AIs always rush for the first move in every turn, for example attacking your retreating army, while you are nearly never able to do that, for example catching their retreating army. You know, a game player can not be faster than the game itself.

I would suggest remove simultaneous turn for ai. Compete speed with AI sucks.

I agree with Option 3. I encounter this problem fairly often. The last minute assimilation action is immersion breaking. I don't like it, even when it benefits me.