Okay, I have a question. I've had my 008 for less than a year and continue learning from this forum.
JoeJ suggests that he loaded the wood and charcoal at the beginning and never opened the smoker. Is it possible that the 250 degree initial setting was just enough to kindle the wood and charcoal and that the combination of fuel could have cooked at a significantly higher temp (for a portion of time) than the 200 degree temp he set for the night? I've done a few oven recipes that called for high initial temps (e.g., 450+) and then an extended period at 200 degrees or so. I assumed that the intent there was to get that outer char or sear and then assure a minimun temp is maintained.
The thermostat on the smoker simply regulates when electricity is supplied to the coil -- it certainly won't regulate the temp in the box when wood and/or charcoal are burning. Assuming there is enough oxygen for flame or smolder the temp could greatly exceed that set on a thermostat.
Could this be the source of both the smole ring and the bark?