Is there any good information around on how the SBR stores the six button presets?

Periodically, and especially after a power outage, I find that some/all of my preset buttons no longer work.

My solution is to use the longer list of favourites that I have to recall the stations of interest and then re-save them by long pressing the buttons, but it drives me batty to understand what's behind this problem.

I can't find anywhere in the LMS app which shows what is stored in these buttons - or am I missing anything?

Squeezebox Radio using LMS 8.0.0 running under piCorePlayer 6.1.0