First off...glad you were not seriously injured and have shared your experience. SPOT purchase in my future.
Edited...remind me not to try and theorize...I fail!
I found this looking thru the new posts today...only recently joined the ADVr forum. An observation I noted while watching the video and subsequent theory...take it with a grain of salt. And something I've experienced, and been fortunate to have some not-so unforgiving terrain to recover in.
It appears to me you were rodeo'd forward (probably not
off the peg/s) onto your tankbag at 5:07. The front wheel came back down after hitting the first step and cased into the next one. Watching your video up to that point there were only a couple occasions where we got a view of the front fender (sat down or looked down), and not so much of it. Feet or just the right foot came of the pegs...note shadow of the fender
not right foot in image below (yes that is the fender...how the hell could a foot cast a shadow in the opposite direction of the sun
). For the next couple of seconds you were along for the ride and didn't have enough runoff to fully regain control. You were trying to...just shit-luck it happened where it did.