Those flipzones are kinda sketchy. Cause if you look at the maps it isn't in the flipzone, Greece, also some play through the claim it and others they do not, maybe it is related to being Solid? I am stable now not solid like last time. Same with Byzantium sometimes they get neutral/barb cities in Egypt and another turn they don't get them. Is there a secondary hidden flipzone? Also in this game Persian Babylon didn't flip to the Arabs, so there must be a factor.
I'll declare war and take the cities back later on, just hope he doesn't get like last times, that some of my troops switch sides, that was a weird bug. He got independence troops when at war from me :s