Mine has always done that. I just scrape it off with a plastic scraper or credit card. If there is limited sealant left I would do as you suggested and add some silicone.
As to the Warrior Service problem I finally called the factory to see if I could get someone to look at the front end of my trailer. About a year ago, I had some work done because the frame was flexing and had cracked around the pinbox. They took apart the front of the trailer, cut out the cross bar infront of the pinbox, and welded in a larger one to eleminate the flexing. Everything appeared fixed until recently. I noticed that the seam covers along all the side edges where the walls meet the front cap sheet, have pulled away and appear to be flexing some.
Anyway, the guy I spoke to at the factory told me they no longer perform service there, but I may have a special situation since it could be related to a repair they performed. Anyway, I need to take pictures and e-mail them to this guy so they can make a random determination as to what if anything they will do about it.