Steve, I just had to post this again so that you, and the readers, could use for future reference.
My first post is below. The final fix was when I bought a U shaped piece of pvc pipe and stuck it into the ventilation pipe to prevent rain from entering the pipe (call it a gut feeling or a last desperate attempt). After three days of drenching rain (that ended last night) I have no leaks! (thanks Steve for all your suggestions)
Recently I had my house remodeled and asked the contractor to look at the leaks I have on the ceilings of two of my baths. The leak is in the corner of each bath where they share a wall. Directly above the ceiling is the attic and nearby is a ventilation pipe that goes up through the roof (I suppose for the baths) and a grill that allows air circulation in the attic. He said that the grill was too far away to be the problem. So he immediately thought it may have something to do with the vent pipe so he had his men caulk around it carefully and caulk in a few other places on the roof just to be sure. He said he didn't see any obvious problems and that hopefully that would resolve it. Well, guess what... I have water soaking through my drywall once again.
Does anyone have any idea what my be causing this? Interestingly, a coworker of mine said he has the same problem in his bath near one of those ventilation pipes, but he can't find the leak either.
Any help or suggestions would be most appreciated.