When I set my MAK 1 Star to any temp the grill heats up to the setpoint and then after I put the meat on it drops back down to -15 - -20 deg below the setpoint and then only goes back up to 10 deg below the setpoint. So if I set the grill to 350 it heats up to 350 and then after I put the meat on it drops down to 340-335 and then slowly goes back up to 340 and will not go above that. I can set it to 450 and it does the same thing, goes to 450 put meat on and down to 430-435 and goes back up to 440 and will not go higher. Any help?