Ok well I have to chime in from my own exp. when I first started I had Ich show up 3 times back then I had no idea what a Qt was nor that one was needed. I tried several methods of treating the fish in fear of stressing them out to get them out of my 125.
Hypo first choice........Great choice if you have exp doing hypo but for me I lost the fish bringing the salinity up to fast.
Reef safe meds hahahaha joke.......Tried kick ich,lifeguard,chem marins stop parasite ect..
and finally fed really well,kept up on water changes,tried garlic soaked foods,beta gluten,ginger root mixed,vitaminc everything I could throw at it...
All these methods I lost every fish (10) in all. Will I ever go back to not using a Qt....Never! It was the saddest thing watching these fish die one by one! I finally talked to someone a few years back regarding a qt tank and since then I have not seen Ich in my tank! My fish are healthy and I never have to worry about them getting stressed and coming down with Ich.
If it were not for the Qt tank I would have quit the hobby!
I personally think taking a fish out and putting them in qt is way less stress than fighting the parasite! and I personally think its our responsibility to treat this fish when they have parasites. This is just MO, not attacking anyone

Everyone has their own way of doing things and Im just giving my exp from having not treated fish with Ich
As Far as the fish having Ich after 8 weeks in cupramine ? Are you sure the cupramine didnt fall below the correct level? or that you didnt contaminate the Qt with your display water "If Ich was present in your display?" Very odd!
And yes that would get me really upset but I dont know if Id say screw the Qt ? Anyhow sorry about your luck,This hobby is not easy and it sucks when you try to do the best thing and have to think about leaving the fish because what a pain the the a$$ it is to start over but personally me I would tear my 180 apart in a sec if it ever got back into my display. Again that's just MO but good luck whatever you decide to do.