I have an 2005 19H and my roof has no such issue. I use a cleaning agent on it twice a year from Dicor. They are the manufacturer of the rubber roofs for Jayco trailers. I would most definitely have it looked at since it is under warranty. Once you get it fixed, a regualr regiment of cleaning your roof keeps it from drying out and helps promote a longer life span.
Hope everything gets resolved for you.
2015 Eagle HT 29.5BHDS
2014 Ram 2500 SLT Quad Cab 5.7 Hemi