You have to ask the moderators before doing interactivey stuff... Have you?
You didn't know about the save-and-popups-go-poof trick?
And... Orthodox Prussia?!
What trick would that be?
So there is no way to save the event for a future choice.
Were all those conversions by event? Or did you get missionaries at some point?
Event. D&T or American Empires must have added an event that converts with a very small MTTH.
Well, it's as you said. If you save and quit, popups go poof.
Even bad ones.
Now it's time to take back the land they took away from you!