Get the trailer under that cover as soon as you can. I think sun damage is the reason some roofs have to be resealed every year or so. My JayFeather is 10 years old this year and I haven't put any additional Dicor on the roof yet, since the factory stuff is still bonding tightly without cracks, voids, etc. But, I keep my trailer under a roof, so the sun can't reach it except when I'm out camping, which is a relatively few days a year.
I saw a model just like mine at a dealer's when it was about five years old. It had obvious cracks in the roof sealant. I'm sure it was due to spending those five years under the sun without a roof cover for shade. In that case, that roof should have been resealed with self-leveling Dicor, but the owner obviously didn't look. As a result, that trailer did show signs of water damage inside, which was the reason I looked at the roof and saw the cracks.