Can't swear to it, but I seem to recall a problem with gold/tin
interfacing.
Gold migration?

Where I've seen this, is when the tin frets, with flakes of tin oxide that
build up under the gold, and literally push the fingers away. Tin-Tin
allows a gas-tight contact that dosen't fret, but the tin-gold is bad news,
in a finger-type connector. Motion, even micro-scale heating and cooling
motion, makes it happen.

I just helped a client through one of these this winter, someone changed a
part number and ordered tin connectors for one half of what was supposed to
be a gold-gold pair.

A treatment of De-Oxit helps a lot, but the real solution of course, is not
to use tin against gold in that situation..

I don't know if it would affect something like a PL-259 though.