I’ve read through all the posts about this issue. There’s enough complaints, concerns, questions, etc. that it’s clearly a flaw in the system. Here’s what I’ve figured out so far; the ash isn’t falling through to the ash tray which in turn is causing a buildup so thick that the pellets in the auger are igniting, and eventually getting back to the hopper. I’ve had my KC Combo for 5 days, cooked on the smoker side 3 times (the 3rd time I got the smoke in the hopper/pellet box). I vacuumed out the fire cup, which had an insane amount of built up ash and un-burned pellets. I ran the auger (prime) and for three full rotations I was getting burnt and/or discolored pellets. I didn’t stop until I was getting only fresh pellets. I then emptied the hopper from the back and I am currently burning off the remaining pellets in smoke mode. I have already submitted a support case with PitBoss to see if they will do anything to correct this issue. If you are having this same issue, I urge you to register your grill and submit you’re own support case. I will update this thread as I learn more and/or hear from pitboss.