Ok, since I have had hassles to reply to my own post, here is what happened. The toilet in the master bathroom had a bad wax seal. Wrong size actually and somehow it started flooding the floor UNDER the tile. so we ended up taking the toilet up and putting the right size in, the floor is very wet and we are trying to dry it out, it actually flooded under the bathroom and into the adjoining bedroom under the carpet and tile, not an easy dry-out situation, I will post tomorrow and let you know how dry we are at that point.

Big pain in the butt. The water marks in the ceiling are likely condensation from the shower and not roof related. the roof is fine.

All in all, with the leak detection service and the plumber, probably about $400 total, now as long as we dont' have more water damage, that will be a relief.

Thanks for all your advice, it was a strange situation and I am lucky we found out when we did, hidden flooding can be a very expensive fix, hopefully this is the end of the story.