Anyone, anyone...? (Continued)

Posted originally in the Plumbing Section, but wondering if this may be an Electrical issue??

I’m guessing the new copper pipe might be type M is is much thinner copper then the older copper that can be type L. The ground bonding is causing the new pipe to oxidize, while the older Type M pipe is not effected and also the pro-press at that junction might only be touching the pipe by the o-ring. But I’m probably wrong as I usually am.