Weird people are not having this issue. Every game since 1.31 i have run has had an AI issue. Basically they will not take over planets. There are some transports but they dont do anything. All what happens is the AI floods your area or another AI's area(who ever they are at war with) with tons of ships and they just all sit there and dozens more just come over and stack but they never will take any planets. Then if for some reason you do end the war the AI will just shadow every fleet/starbase/scout with one of their own ships. Its like the AI is still trying to attack your ships but they cannot so they just follow and sit next to them for pretty much ever. The game usually becomes very boring by then and i end up restarting a new game hoping to get an AI that will play the game. So far no luck.
Doubt saves will be useful since my game is very lightly modded for quality of life and on a custom map, though i cannot imagine modding some of the techs will break the AI.