If it was LOS then you would have completely lost video signal then I guess. A head scratcher in the works...
Firstly the servos centering when control is lost is a common setting caused by the Failsafe function upon Loss of Radio Signal.
Secondly the VTX and the Radio control use 2 separate radio channels and transmitters so it is possible to loose the control signal and have the video signal continue.
Normally the battery is shared between the radio control and video systems and so a loss of both could indicate a loss of battery supply, (a brownout).
From what I have read in this thread there was a loss of control caused by a LOS which looking at the wreckage is somewhat reinforced by the remains of the radio and servo installation!
No mystery about this at all!
Have fun!