I'm not sure this is a bug or intended but it seems that sometimes AI Cores just disappear in the AI Trainers occasionally?
Based on the % chance outcomes it should be 100% to get some outcome but I notice sometimes it just seems to disappear. I have inserters for each of the 4 possible outcomes and none even move after a core is done training.
I've seen it happen at multiple core levels.
I've disabled all mods on my save besides Moshine and K2SO and I see the same behavior. Haven't tried a fresh save with just Moshine yet.
Example below: T9 -> T10 , first time it loops into itself , so T9 stayed T9 and went back in -> 2nd time it just went poof (sry for the quality)
https://imgur.com/d6Dsvu5