I also doubt I have wisdom on this. Just a couple of observations. First, I cannot explain the quick rise to 165 - no clue why, unless the probe was too close to the surface of the meat.
But, based on your temp and time numbers, the "stall" occurred about at the right temp and look a good long time, so no real surprise there. The finish temps are a puzzle, I can't see how the thin part of the flat can be at lower temp than the thick part that was done right, except for a thermometer not reading right for some reason (maybe sticking out of the overdone part of the flat and going low with the door opening?). My uninformed conclusion is that there was some thermometer reading error in one or more places during and after the cook. I am no brisket expert and mine have failed more than they have succeeded, so these are just my $.02. I hope you try the same scenario again with a different cut of brisket and report back! Thanks for the thought-provoking post.