I watched the vidoe again only to say WTF... If you look there had been a battle for that spot for a lap. Well heading from turn 2 to 3. The orange bike gets the front wheel off the ground, then shuts off the gas (braking mistake). Meanwhile mr 944 flys right by like he is standing still. This move didnt just show a wheel, it problably showed the back wheel (a complete pass).
Now if you look at the impact. You 1st see the front end of the orange bike, then arm and then his thigh indicating the orange bike was moving faster. This to me shows a over agressive braking mistake causing the crash.