I'm glad I'm not the only one! The noise was driving me crazy, after I ran over a rock that got dug up while climbing a sand dune. All sorts of weird conditions to get it to show up. I didn't have as much of a formal fix though. I just had a crowbar and some Jack stands to pull it kind of back...
I haven't had great luck with sand mode in deeper sand on an ascent. I've had better luck with sport mode. We just tried it out this past weekend in some California dunes. All else equal, we got stuck in sand mode but cruised up in sport mode.