pin holes in copper pipe

Hey everyone, new to the forum. I was wondering if anyone else has had problems of copper pipe corrusion a little while after installing a gas fired tankless water heater. About 6 years after installation I started having problems within 12 feet of the heater. Two different area,s. So far I,ve talked to three people with the same thing all with tankless heaters all on hot water lines close to the heater. There will be a little spot of green corrusion then a pin hole will develop. I appreciate any help I can get. Thanks Dennis

Did the installation of the tankless change the electrical continuity of the the copper piping? What I mean is there some sort of electrical isolation now?

Some theories of pinhole leaks suggest galvanic corrosion. Tank heaters have sacrificial anodes.

Heat accelerates corrosion. I would do a complete water analysis.