Thanks Eddie, looks good. It's only in one or two spots so far. I contacted Keystone and they passed the buck and said ask the dealer. They recommended a marine silicone. They say they carefully dig out the old stuff and reapply. I told both of them that silicone doesn't stick to EDPM. They just ignored me. I think because they no it was a goof to use silicone there.

My plan was once in the US to pick up a couple rolls of Eternabond tape and cover the whole seam and then use Dicor lap sealant all along where the Eternabond tape edge meets the roof EDPM. Figured that would make a great seal, I really don't care how it looks as long as it is a good seal for years to come.

But now that I see your suggestion I may have to rethink the solution as that stuff sounds pretty good. Thanks!

Yep Ray, we got the same response from Keystone. The good thing about the roof rubber coming down to the side gutter is it laps over the sidewall and is covered by the gutter rail. I need to seal all our gutters soon like you.
Happy Trails!!!