I put this thing on last night at 7 PM for an overnight smoke. My smoker (for some reason) was all over the place all night, mostly on the high side. As high as 320 for no reason (nothing changed) and as low as 180. It stalled at 145 and now some 17 hours later is only at 165. I checked it with a couple different probes and a different thermometer, so I think it's okay. I've never had an 8 lb butt take this long to cook but can't figure out what could be wrong. Any thoughts?