Bottle it on the tight left hander and too much front brake?
Ive watched it a dozen times & I cant for the life of me see how it happened. He was quite wide so I guess he didnt leave much room to allow for error if he was going in hot. Might have hit some loose chippings on the first slip, causing him to panic brake, causing the second?
Frame by frame shows the wheel stops spinning as it starts to slide so definitely braking locking the wheel.
Not sure what is going on though. Starts the corner wide as he should, but is suddenly close to the centre line markings when the wheel locks up. So close that as the wheel locks the white line is taking up the left half of the view (watch every frame from 0.28 to 0.29 to see what I mean). I can only assume he was taking a racing line and saw something he wasn’t expecting round the bend.
Yeah - I think he felt he was going in too fast and was out of his comfort zone - he panicked and started braking and lost traction on the front.
Whereas if he had just hung in there feeding in a bit of power he would have got through - easily said from behind the safety of a keyboard I know . . . 
I think it’s one of those situations where (if you can) you have to remind yourself that your tyres are much more talented than you are and will get you round the bend if you just let them.
We can’t see round the bend as far as he could, but it looks like he had plenty of room to go wide.
i don’t think he saw anything, you can hear the footpeg scraping right before the front unloads & slips away…
Wasn’t watching with sound. As you say, there is a noise just before the wheel stops rotating.
The camera angle dips before the wheel loses traction which might suggest he pivoted on the grounded foot-peg.
Yeah as above, looks like he/she ground the peg out mid bend…
So perhaps that shook the rider up, panic brake or throw the bike upright, offset the weight balance, throttle jerk, loss of focus, etc etc…
Is that a BMW?
+1
Yes - absolutely right.
the tyre pressure dont look good could that have caused it to happen too ?
I’d say something grounded raising the weight off the wheels. there’s about half a sec of abnormal noise and travel before the fall starts. grounding raises the bike up off the traction point so bike travels in direction of force, not steering input, front becomes useless, down she goes… reasons are anyone’s guess