This may be totally unrelated but I've played certain venues many many times and the sound will be different each time. It makes me very upset
Another example would be our practice room, the bass guitar sounds different and shit weekly!! I constantly change the bassist settings, no idea why I have to do this. My guitar setting aren't changing unless I come up with a new patch and I haven't done that in a while. Particularly with the Rockmaster pre. It's set and forget for me and the only thing that changes is the actual effetcs I'm using. But for the sake of this discussion say I use the same few patches eveyr week, and yet every week I seem to need to change the bass. No atual fault with the gear, but some other phenomena.
Sometimes I get random issues also like one side of my one of my rocktron poweramps has intermittent EQ knobs and I don't know if the pots will need replacing or what (if I jiggle them etc I can get them to work correctly but they will drop in and out). Anyways this issue caused me to think there was an issue with the speakers in my cabs. Totally sent me off on a wild goose chase.
Another phantom isue I get sometimes is when I'm not warmed up and everything feels stiff to play and then I think I have lost distortion as the spongeyness isnt there or something when actually it's juts my own hands aren't ready to play! Probably none of what you are experiencing Soloist but some similarities may be??