The case from the Brazilian slide was fired using the same frame, so I don't see the frame being at fault here.
I never fired the gun with it's original link because it was so crappy (see photo below) and the lockup was so bad.
I did install the crappy link and "fired" some of these cases with the off-center indents. That resulted in the strike being more centered; not perfect, but better. Tomorrow or so I'll take it out and fire real ammo through it. I may fit an extra barrel tonight just to see how the centered the firing pin is with it.
I'll measure the slide tonight and see if it's out of whack.
I can just put the Brazilian slide on this frame since it doesn't have a "home" at this time, but I'd rather not admit defeat this quickly.
I probably need to get a link assortment, which may result in getting the firing pin centered, since I think I think it's a high/low issue.
I had originally thought this was a hammer problem, but a new hammer and mainspring had no effect. Once I looked at an empty case the reason became much clearer.