They have never been delayed in my first playthrough. I did the same thing as you in Chapter 2, I didn't invaded the last capital until I had exhausted all political decisions, and having finished the storyline of my princess and my generals, ie until turn 106. After that, even if I reach 100% of approval to all races, no more political decision or faction decision is triggered (every third turn of course).
In my second playthrough, I'm currently at turn 34, in which instead of having a faction decision (90% Imp satisfaction), I have a lambda political decision. And if I pass the turns quickly to increase the reputations of each faction through the Demon Corvus at 100%, even reaching the turn 90, I have no more faction decisions that triggers, only political decisions until I exhaust them all.
