2. I did load a bin full of pellets, problem is fire went all the way to the top of bin , i guess you can call it a burn through, or total burn inside fuel bin.
If your water tight seal works, there will not be smoke out of cover. Burn can only happen inside burning element, the position against the air inlet.
Do you add lining on top of burning element. the lining also acts as seal.
If no lining, burner may happen a little higher than burning element
Regarding controller, I never meet this problem. Seems strange. I need you to send back for exchange a new piece. As a compensation I can send you an extra meat probe