It is funny how people blame TC manufacturer for rot problems after a few years when ever manual tells you to check roof / lights / windows ever year to see if they needed to be re-caulk AND they do not and then blame problems on what ever TC they got.
Folks these things bounce and twisted around when you travel things break sealing becomes loose or crack.
Check ever 3 months and you will not have these problems.
My first check on my 2012 Adventure roof showed 2 areas that had to be re-caulk.
What you think would happen 3 years down the road if I had not checked.
Hell I did a check on hour one of owning camper just to be sure;)