Can't reproduce. Second one this thread where someone had this error "for years" but I can't reproduce. Smells of a setting that's been migrated for years from an old version, as where I'm writing from is a clean macbook with a clean account (M3, about a year old now).

EDIT: can repro. But it's very important to note: you need to have a color selected already. So select a color with the + sign, close the app, open it, top right click custom color, and then the bug appears, although not like you describe: the color selection is easy, it jumps around for 20ms during dragging. If this is what we call "low quality" I'm happy to stay on Mac.

Might be a reason why it wasn't fixed if you didn't include that vital step in your repro.