Ok, this is going to sound crazy but....
I've posted before about my lower door becoming very loose, a minor annoyance of the FMVV, so I decided to try the trick of putting one end in a clamp/vice to tighten the door tension fit. As I was doing this, the unit slipped out of my hands and took a a 2 foot fall onto the floor. Both doors came loose and went flying, I also forgot the herb chamber was full and I lost a full load. Neither door would go back on and I noticed that the whole thing was now seated a bit crooked in the outer housing, the recess to fit the doors on was now much less shallow.
As I pondered what to do now, a bit perturbed at myself, I dropped the unit again! It took a bit of a tumble on the wood floor, but when I picked it back up, it looked like the impact knocked it back together straight and it was now seated properly. The doors snapped back in and they were now as tight as when it was new, even the bottom one, actually, the herb chamber door is now almost too tight. I haven't used it again yet, but the heater seems to heat up fine.
Needless to say, I am somewhat astonished that I fixed it just by dropping it! I can attest and verify that the build quality of this thing is quite good.
Edit: It is probably the responsible thing to say "Kids, don't try this at home." I don't want anyone to break their vape trying to do on purpose what I did by accident.