copper and acid core solder

[pitrominca]

I'm new in this forum and this is my new post so first things first: I want to say hello to everybody.
My question may be stupid but it is bothering me a lot. A couple of years ago I made on my old house a chimney flashing with copper and solder the seams with plumber flux and solid 50/50 tin /lead solder. Being not expert I showed the final product to a friend who decided to make some improvements soldering some seams which I left open with acid core solder. I mounted the cricket flashing and forgot it. Recently I read somewhere never to use acid core with copper. So I'm starting to worry. Can anybody give me his expert advise? I'm I in trouble? Thank you very much.

[NC Cams]

Copper pipe and flash have been soldered with acid core for years.

The person nay have gotten that confused with copper wIRE.

Copper wire should only be soldered with ROSIN core solder.