I'll add the same welcome. I'll don't have much to add on the shoot-in problem as I don't use pellets. My TC firehawk wont shoot them as only one pellet goes off. I assume that your on a good solid rest with no foward hand pressure torking the stock. You are probably correct on the over cleaning especially if you use any kind of liquid between shots that might partially wet a pellet. I run a copper brush after two shots then shoot two more ect. Otherwise, everyone else has pretty much covered it. Good luck!
I do use wet patches but follow up with dry ones until the the dry ones come out clean but maybe there's moisture left on the face of the breech. I'll check that next time. I'm fairly confident with my shooting rest (sand bags) and position as I don't think I changed any of that from last year.
Thanks again Hunting Man for the welcome.