[Digitalis]

I still can’t figure out how the focusing could only be affected by one camera body, when in theory it shouldn’t matter if its even mounted to a camera at all.

I hear ya I'm stymied about this problem as well, and as an above post mentioned the MK-mFT adapters are basically extension tubes so I can't see what is wrong either. My own SMCP-K 50mm f/1.2 is built like a tank so something would have gone drastically awry for there to be something wrong with it.