Clever solution for the chase and pipe.
That orange spot appears to be light surface rust. If it bothers you, sand it off and apply a coat of shiny spray paint to protect the fitting.
Most of the time, if a leak was in this location, you would see and feel traces of oil on the surfaces.
Okay, thanks guys, that "blistering" is likely just traces of normal copper/weld oxidation I'm guessing.
I'm going to try and get a ventilation expert out to the house next to see maybe if he can give an expert opinion on the ventilation situation and what may be going on with the ridge vent in particular.