@Section8 I tested here and I can't reproduce, with the option off, it doesn't search for missing covers when playing radio streams, are you sure it's not already cached cover. Try deleting everything in ~/.local/share/strawberry/strawberry/albumcovers/, that should not affect the local collection songs which have a separate cache dir.

@jonas Good call -- I've traced it to the Linux applet Enhanced Sound, as removing that from the panel resolves it instantly! Thanks, I'll get onto claudiux about it, as I thought I'd turned off any features that involve music players...