I might side with the dealer on this one. Question #1. Only in the powder with it pinned has this happened? Question #2 Has ever happened on the trail under somewhat normal riding? I had this happen to me in my pick up!!! Is snowed and it was powdery and I got to playing in a back field and I had high rpm's and there was snow inside and out of that truck. I got on the road and 3 minutes later I had a stuck throttle. I kicked at the gas peddle and nothing until finally I had to shut the key off. Sure thing, where the throttle cable hooked to the butterfly was all frozen ice and snow. I chipped it out and all was good. If the problem only happens in powder play that might be the culprit.