Leoreth can you tell me which civilizations have conditional spawns?
Conditional on the stability of their owners: Thailand, Mexico, Argentina, Colombia, Brazil, Byzantium
Conditional on the non-existence of another civ: Italy, Byzantium, Iran, Mexico
Can be disabled or randomized: Poland, Moors, Congo, Tamils, Tibet
So Leoreth, how do you explain in my Ethiopia game respawned Egyptians didn't flip their core cities which were under my control? Was it because I was solid? In the same game, respawned Turkey took Istanbul from me, I think I was flat in stability.
Okay, the most important thing to know is that respawns are city based. Either a city in the respawn area can be part of a respawn or not. Independent and barbarian cities are always part of the respawn, for others it depends on their owner's stability level and some other factors.
A respawn is only possible when enough cities qualify, otherwise it immediately fails.
If the respawn is possible, there is a random chance that it actually occurs based on the civ in question. For some civilizations this probability is 100, i.e. they automatically return. Some factors like the spread of Nationalism influence this.
Usually only the cities that were initially considered part of the respawn will flip to the new civ. However, there is also a "critical mass" rule, which means that if enough cities flip, the remaining few eligible cities will also flip regardless of their owner's stability.
Seems like you were in the scenario were Egypt could respawn without the cities under your control, but didn't reach critical mass to receive them regardless.
Also, I feel respawn area is quite large in general. What are they for each civ?
Usually their normal area, which is larger than their core. Some civs have specific respawn areas that are used instead. If you think a particular case is too generous, you can report it here.