I will add this too:
Windows that have been sealed with putty instead of Butyl tape are the worse!
Butyl taped windows should be lightly tightened soon after mfg... 1 Summer! If not, they run a good chance of leaking soon....
If you inspect the windows and the Butyl tape is not oozing out that could be a clue that you need to inspect that window closely. If you see a gap between the window and tape or camper and the tape you need to inspect the window closely! Most of you will not know that they are leaking until it is too late!
Putty around running lights is problematic too. A good sealer is much better.
Easy to inspect and see if they are not sealed.
Jim