Aluminum roof delamination

Hi everyone, I have a Lance with an aluminum roof that's about 13 years old. Recently I've noticed that when I head up to the roof there are areas where the aluminum has detached from whatever it was adhered to (I'm guessing plywood). My question is if it is possible that after some time, the glue or whatever it is that attaches the two together will just fail or is this a sure sign of a water leak? From everything I can tell there is no leak anywhere. I have been pretty good at patching up the occasional crack with Dicor and the caulking around the edges is pretty good. The caulking around the edges could probably be redone though as it is discolored and appears pretty old but doesn't look like it should leak. Nothing leaks in the interior and there are no signs of water damage anywhere. I'm perplexed as to how this all of a sudden just happened and then how to remedy the problem. I've searched plenty on the forum here and it's unlike any delamination issue I can find.