How are your provinces becoming secular in the first place?

I played Confederates got secular then this 100 messages came, but only a handfull are really secular it seems, i changed too protestanism again thought they stop then but didnt work. I will convert the secular provinces maybe it will stop then. I didnt payed attention if the messages change really the religion, they come without reason.

Ok after i changed the four secular provinces the messages dont come anymore ty.