Haven't been in touch with Masterbuilt, yet. I will tho. Been busy.
To answer somebof the questions, nothing in it to disturb air flow. I smoke right on the racks. No stones/tiles, etc... the unit is almost four years old. Fairly lightly used, overall. I keep it outside on my deck covered with a patio chair cover and a LG plastic bag under that. I did notice that there was a tear on the cover when I took it off. That may have had something to do with it, but that'd be weird 2.5 hours into the smoke, no? I only smoke when I'll be able to be home with it the whole time (or else someone else might drink my beers and smoke my cigars!!!).
Might just be "one of those things"- you've heard of Murphy's Law? I'm the Murphy they wrote it for!
Might just be "one of those things"- you've heard of Murphy's Law? I'm the Murphy they wrote it for! But I thought your name was Brian...