Description: AI built city on place of their own outpost ransacked by me in Neolithic Era, in attached file you can see that Assur is missing the Main Plaza

This is how it looks on my side

Interestingly enough, Independent People's outpost I destroyed appears just fine in Dubhe territory:

Assur missing Turn 117.ctr

I had a similar issue with AI's ransacked outpost missing Ruins model earlier in this game, but haven't thought about preserving a save with it, sorry.

Okay, I've did a quick replay and this seems to be much more elusive than I first described it to be:

Outpost ransacked in Neolithic, as expected from the bug, the tile appears empty:

the tile becomes empty (save: outpost_ransacked.ctr)

All right, let's build our own:

it appears no problem and Main Plaza is there (save: main_plaza_present.ctr)

and I go further and wait patiently for AI to retake it:

they attach territory and it appears without issues.

So the ransacked outpost does disappear, but I have no idea what caused Assur to vanish previously.