Most of those accidents with high HF involvement would be landing crashes, I'd have thought. Those seem to make up the vast majority of MQ-1/9 incidents that I've heard about.
I'm interested in fltlt's comment; I was under the impression that as soon as the drone stopped receiving inputs from home, it'd undertake a pre-planned flight to take it home. I'm yet to hear of one stop listening, but not realise it had stopped listening....?
That would result it in just carrying on doing what it was doing until running out of fuel, I guess, but surely that's as rare as a total hyd loss/catastrophic multiple birdstrike that would similarly leave a GR4's crew unable to influence its final position?