Yeah, great !
I'm sorry to say, though, that most likely you'll have to do another version
Just tonight I stumbled upon what seems to be a regression to around 1.15 (i vaguely remember reporting such a problem around then):
AI (Norak) offered alliance, with intersettling and complete(!) tech exchange, and all goodies on turn 41.
Thing is: I'm not bordering them, I don't "see" them on the map, I may have shot down one scout 20 turns earlier. No trade, no previous treaty, relations are "unknown".
Either the AI is (again) too fond of intersettling/alliance treaties, or this is that "errenous treaty message in the turn of meeting them" bug, which I had once before as well. Might actually be a indigenous SE5 vanilla bug, don't know... .
Savegame appreciated?