Yeah, in my case I lost 2 flames during Cupramine treatment. Again, I can't say it was the Cupramine with certainty, but that was my experience.
Well, in my case, all other things being equal (same salinity, same salt, same temperature, same level of NO3-, etc.), the only difference was that the fish only system has copper, and the coral systems do not.
Sixline wrasses (although not the other members of the pseudocheilinus genus, bizarrely), anampses wrasses, seem to be badly affected also.
I see people claim all sorts of wild things about how badly copper affects whole slews of fish, but those are really the only ones I've seen die within days on a consistent basis from therapeutic copper levels.
Obviously long term exposure (6-12 weeks, from my experience, depending on which fish), will negatively impact any species, as copper wreaks havoc on the internal organs of fish, but in the short term (i.e. QT length), it's fine for 95% of species I've encountered.