This is being discussed at length over on a African hunting forum that I am on. The big thing is that they are saying that both the hunter and PH should of backed out of there and let the lion settle down. Another thing that they observed is that the lion was chewing on a stick which most think is because the lion is hungry.
It comes down to the fact that the hunter should of never taken that shot with the crossbow and that the PH did his job protecting the hunter, and himself along with the trackers who were involved in the hunt.
I haven't read if that lion was a captive bred lion that was let out of his enclosure to be hunted yet, but the consensus among most of the lion hunters on the forum is that he was due to the condition of his mane and other things.