Does anyone have similar problem where the splits closest to back wall stay black and less (not) red-hot coal like. I find that I need to poke the disentegrated split to the front to burn a bit then reload in ten minutes, I load it full, stuffed, wood hitting top tubes. I get burns easily up to 500-550 before begin to dial down. I usually leave air open 5/10%. Also, I find that once I dial down, temp continuously drops, not cruising per say ( from 600 down to 300 in 2 to 2.5 hrs) So is this common, blackened wood in the back? Thanks