Well, right or wrong (and I lean toward ‘wrong’) I know many folk that carry that figure they’ll only shoot about ‘a double arms length’ distance in a self defense situation. That is, they’ll have the gun darn near touching someone when they shoot.
With a belief like that they also believe they only need to shoot the gun enough to know that it will go off when they pull the trigger and that their ammunition works without any problems like you found. For these folks a couple boxes of factory ammunition would turn out to be a life time supply.
I think you were right to get rid of it since you have other guns you like much better and I totally agree that the thing could have screwed up your shooting ability. The smart way to break a bad habit is to avoid it in the first place if you can.
For me it is pretty convincing evidence that you were getting some vicious recoil because ammo that worked in your other .44 mags was jumping the crimp in the 329.