I am in the process of seasoning my new #2 and I am scratching my head. I purchased a Maverick ET-732 and calibrated it with boiling water last week. I put the probe in the smoker to see what the box runs at during the seasoning. Started up the unit, set it a 250 and away we go. It has been on for 40 minutes now and I am seeing temperature swings up to 320 degrees. Should I see this with the smoker being empty and all or should I have a concern?