I can try and provide screenshots. But every time a new neutral AI city spawns, the Pink AI person gets instantly a +3 to its relationship to fill in the bar.

Happens to me and friends every game, it sucks because it means pink/magenta always beats everyone to the new world no matter what you do which is a great grace period for players boxed in who went trader or non military.

Posted a similar report earlier today
https://www.games2gether.com/amplitude-studios/humankind/forums/215-bug-reports/threads/42974-pc-steam-player-ai-in-third-slot-always-gains-relations-globally-with-independants?page=1#post-328849

happy to see this issue getting a lot of attention because this bug destroys the colonisation era when one AI is already assimilating all the natives before anyone discovers it.