I have noticed it on KXSR, which sounds as if it rebroadcasts a grainy KXPR off of a standard FM receiver. I put it down to that issue.
However, I know they have a permit to move off the tower in Walnut Grove to another site near Sloughhouse. They’ll be closer to Sac and the eastern suburbs and will probably provide a better signal in those parts, but they’ll lose about 30m of height off the antenna and be able to go non-directional. Perhaps it has something to do with that…