Thanks, but it concerns me that, since I can't understand why, then I
may be missing something, such as a condition where this could be a
temporary fix in the end.

I understand exactly what you're talking about, but it simply isn't
productive. There are better ways to use your mental energy.

Pots (or the circuits they regulate) can and do drift. I've bought several
of the original Sony FM Walkman, and all have required the stereo sync pot
to be readjusted (by ear is sufficient) before the tuner would switch to
stereo.