Hmm WTF is going on

[Tim Curtis]

The symptom "it works then after a while it doesn't" suggests something external to the software for example a power supply issue, bad connections, etc.

1. If you have electrical contact cleaner unplug the pieces, spray on the connectors and then reattach everything.
2. Swap in a different power supply if you have one

lol, when my one cat was a kitten he liked to try climbing up my Collie's front leg :-0

Yeah, I was thinking more hardware than software, as well. Curious though, that the “fault” only happens when I “clear and add” a new track. Higher processor load perhaps? Which might then point the finger at the PSU.

Let the “parts swapping” commence…….

You mean "Clear queue" then "Add" a track?
There is no Clear/Add option anymore. It was removed long ago.

In any case someone will need to repro your issue in order to troubleshoot it otherwise its just a "wild goose chase".