Ah ... I didn't see your post until now, and wouldn't have known the answer — but I had a chance to test that out earlier this evening. Yes, it does about the same thing when I crank the knob around to the Spin setting in many of those other modes. So it isn't just that one particular position that's worn out. However, it doesn't rule out the relay you mentioned. There's no way it'd have separate relays for each mode ... which means that a sticky common relay could give the same result in any mode.
I think the conclusion would be, "prrrobably a mechanical issue, but still the outside possibility of an electrical contact issue."
I think the conclusion would be, "prrrobably a mechanical issue, but still the outside possibility of an electrical contact issue."