As this is rumour network; I will add to it:
-it seems to me there are two options:
-after botched landing, copilot went to inspect the damage and accidentally fell out ( dont`know where from, as on landing videos/photos there is no ramp/door open)
-after botched landing, that obviously caused damage to the airplane (maybe not only wheel, but considerable more) this young lad, that was PF during landing, completelly froze, realizing that he caused quite some damage, etc. and bailed out of terrible situation-literally.
At my place, it is MANDATORY for parachute drop pilots to wear a parachute - there was more than one instance in the past, that I am aware of, that a parachuting incident caused an out-of-control situation that required everybody to bail out. (example: due to premature/unintentional opening of parachute while at the door, canopy caught into horizontal stabilizer, jammed elevator, added drag and airplane was diving vertically a few seconds later with elevator controls firmly jammed by fabric, wedged between elevator horn and stabilizer.)