I just noticed the paint bubbling up from rust on my 2 1/2 year old Sprinter. It was a small spot near the water inlet. I pulled the fitting off and found considerable rust. I pulled off the electric inlet and it was even worse. Lots of paint had gone away. Turns out every hole Sportsmobile cut was rusting away. I sanded the rust down to bare metal, primed and painted. I'm so glad I found it when I did. I don't know why Sportsmobile didn't prime the cuts.
That's a serious bummer. I'd be pissed but honestly it doesn't surprise me that SMB doesn't take the time. I've seen lots of corners cut in their work.
It's pretty sad they couldn't treat the edges of the raw metal left behind. Everyone knows that rust will quickly follow. It's good you found it before it got worse.
It would seem that if there were sealer or a gasket in the joint water would not get in. Were the fittings just bolted on with nothing sealing the fitting to painted steel joint?
I'm not surprised. That's the kind of attention to detail SMB fails to do. I don't get it, it's an obvious future rust spot that takes minimal time and effort to do correctly- mind boggling.