Ok I went a few turns back to an autosave and tried to reproduce the bug. Turns out it wasn't the peace agreement (assyrians didn't ask this time to make peace with russia) but something else cause after I ended the turn, it happened out of nowhere - all res zero, can't offer them to AI, but all still visible in city screen. You should be able to reproduce it by pressing enter. I really would like to continue the game so I need your help badly O_o
Edit: I added the turn before the turn it happens cause after loading the 91 AD turn I saw it already had happened although I saved before that...strange... the 88 AD save should work just end turn one or two times
Edit2: I loaded the 88 AD save again and was not able to reproduce the bug this time. Good for my game bad for the debugging, I guess. However, what I can say is that the two times the bug appeared, suddenly I had no res to trade to other civs and they wanted to trade me their feathers, baskets, whatever of which I had several sources - they were not able to try to sell me that crap before the bug (cause I had enough).
Maybe the broken saves (112 AD in previous post, 91 AD in this) may help you after all, in the cities you see the res I have [but which are not recognized by AI] with numbers behind them like cow (56). Obviously I had not 56 cows, so there must be a bug in showing the right amount... what could make it that the trading and showing of res gets broken?
Nevermind, the bug is on the record now - so long!