Grain Setting Mysteriously Moves By Itself

When I'm not looking at my computer, the settings for grain readjust themselves. Always to the same point. Grain 56, the other two to 38 and 39. I don't touch anything. I'm sleeping, I'm eating dinner, then I'll go to do some work and when I open up a picture, it looks like a mess. I used to panic; now I just scroll down the grain section and always find that phantoms have increased the grain drastically, and always to the same point. Weird, huh? Any ideas?

I'm running Lightroom Classic 13.3 on an iMac loaded with Sonoma 14.5.

Many thanks, in advance.