Coastal, I've seen seams on the roof open up from my weight on the roof.I've taken that as an indication that the Vulkem was oxidized and due for replacement. I noticed this particularly on the long seam where the awning holder is riveted to the roof. I scraped out the old Vulkem, replaced it with a new bead, and added a layer of aluminum tape for extra sealing.I suspect you are correct.
Nick Crowhurst, Excella 25 1988, Dodge Ram 2500 Cummins Diesel. England in summer, USA in winter.
"The price of freedom is eternal maintenance."