I have a Green Mountain Grill smoker. Today when I fired it up it was taking forever to heat up. I restarted the cycle, removed the pellets from the hopper and it seemed to do a little bit better but not like it usually does. There was inly a moderate amount of smoke coming out. All of the sudden I heard a loud pop, the lid jumped up a couple of inches and smoke started pouring out of it. The temp climbed rapidly from 95 to about 140 and then leveled off at its normal rate. Anyone else ever have this happen?