Hi...I'm fairly new to smoking and I built a UDS. Done several smokes on it and everything's been great. Put an 8 lb pork butt on last night at 10:30 P.M. stabilized temps at 250. Temps this morning still read 232, but internal temp was 162. Went to work, came home UDS temp had dropped to 180, internal temp of pork butt reading 175. I brought temps back up to 235-240 and it's now 17 hours later and I'm still getting an internal temp of 180. Bone wiggles...I've used two different thermometers and they are both reading the same thing. What am I doing wrong?