Freebird, I have seen this situation on a very small percentage of stoves but always with the fresh air intake hooked up. Do you happen to have this? I have never found anything connecting the pellets or sawdust or foreign objects to this. This is an issue your dealer CAN and SHOULD be able to help you with. The retrofit of the air intake will reduce the vaccuum pressure inside the hopper. On all machines that I've seen modified the problem immediately stops.