On the video the sequence is:
~ descent
~ touch
~ bounce
~ aircraft ascends to about 5'
~ aircraft still in controlled horizontal hover - power clearly feeding to both fans
~ aircraft suddenly pitches nose down
~ nose hits ground
The newscaster states "the nose gear appears to snap off, sending that jet spinning out of control", but it was nothing to do with the nose gear - it obviously broke, but that was well after thrust from the front fan had gone.
Or maybe, thrust from the rear nozzle suddenly increased to cause the pitch down. Could that happen? There are white vapour emissions from the rear nozzle area during the descent - are these normal or possibly a hydraulic leak from the nozzle actuators?
Does the F-35 have an afterburner?