X2 on what shadow said. It is all part of the "RV experience"...sealants leak over time and the only thing to do is re-seal; it becomes an annual event around my place, inspect, repair/reseal. Don't let it go...water where it isn't supposed to be is not only a hazard to the integrity of the trailer, but, mold and mildew is also a health hazard in large enough quantities.
My 2 cents, your mileage may vary...
2 Cats; J-Lo and Ragamuffin :R
2014 Thor Tuscany 40RX DP
2011 Ram 2500 Longhorn CTD HO
2011 Keystone Cougar 318SAB (now gone)
2008 FunFinder X 210WBS (Sadly gone)