Just because water is not making it INTO your camper does not mean the roof material is maintaining a seal. If it is a small leaker that only leaks in a heavy rain, the outer luan plywood simply may be absorbing all the water.
Lou and Laura with Bella - German Short Hair Pointer
2008 GMC Sierra 2500HD Crewcab SB Allison Duramax
2010 Flagstaff 8526RLWS - Superglide 3300
HAM CALLSIGN - KC3FFW