A little light, a bell, a fog horn, a flashing strobe, a fire alarm and an all out air-raid siren just went off in my head. If nothing else except the pellet has changed since the problems began, then trying a different pellet might be the logical next step. Those pellets look like chit, all dusty and crumbly. Possibly because they got wet bot also possibly from getting ground up in a defective feed system. Lets rule out the pellet first before we go switching out a few more hundred dollars in parts. I have serious reservations that this is a stove issue.
I think you misunderstood what I was saying. I have experienced this problem with three different brands of pellets, including two that had worked fine last season. The pellets look bad in the picture because they have been ground into a big clump by the auger. When I put them in the hopper, they are smooth and pretty uniform in size, with very little fines in the bag.