You don't have problems with the frame counter on your Minox? Are you sure? I had this problem with two of my Minox A cameras. Of course, I didn't notice it right away, because who checks the frame counter before and after each shot to make sure it's working properly? However, you might wonder why a few frames are missing at the end of the film. That could be the reason.
I've written down my thoughts on how the Minox frame counter actually works and how it can be repaired here:
I had a Minox A IIIs with an unreliable frame counter. Most of the time, it counted up by one frame when cocking, but occasionally the advance mechanism
Nope, never had this particular problem. Not with my B (used 1967-1969) or my IIIs (used 1995-2018), or my later B (used 2003-2009). I had other problems that required repairs on the IIIs and later B - like mechanical lockups and uneven interframe spacing - but not a frame counter issue.
However, I have a Leica IIIf with a bad frame counter, and an Olympus Pen S that had one... but it seems to suddenly be working correctly on its current load.
Nope, never had this particular problem. Not with my B (used 1967-1969) or my IIIs (used 1995-2018), or my later B (used 2003-2009). I had other problems that required repairs on the IIIs and later B - like mechanical lockups and uneven interframe spacing - but not a frame counter issue.
However, I have a Leica IIIf with a bad frame counter, and an Olympus Pen S that had one... but it seems to suddenly be working correctly on its current load.
That's interesting. I hadn't heard of this problem anywhere else before it happened to me. But at least other camera models seem to have this problem as you mention.