I've had faction decisions delayed quite awhile before being triggered. Playing through the story campaign I tried one option for my wife to see how it would turn out, intending to reload, and got the undead's second faction decision in before seeing the result. After reloading, the undead sat at 100% for some time before it came up again.
There are political decisions every third turn, so a few random political decisions can delay a faction decision for awhile. Loading a save near the end of the game and just not invading the last country, it took until turn 76 to get the last of the faction decisions (and the imps, lizards and undead were at 100% on turn 45).
