Water intrusion is a problem, for all RV's. Had a problem with our Tiffin, years ago, with the side drivers window weep holes which weren't draining very well. Fortunately caught it early, could have been disastrous as transmission, Jake brake and lots of other electrical controls and switches were on a ledge just below that window. Drilled more weep holes and made sure they were kept clear, never had another problem with that window. If you suspect moisture intrusion, do not delay identifying and correcting the problem.