I'm one of the oridgnals in this thread,
I'm 99% sure it's software and how it handles reconnecting.
I'm on 3uk (three) with that Ive ONLY got 3G,
No EDGE or LTE.
So in a bad 3G area where other phones on other networks may drop to edge and
Back to 3G without a problem (sometimes to much switching if some reports are true),
mine can only go from 3G to no service.
That's when this fault kicks in.
Im sure it's reconnecting to 3G where the main problem lies.
If it could reconnect to edge 1st, I think the phone has no problem switching from
Edge to 3G once it's got a signal already (& then onto LTE).
Some reports I'm reading is its fixed in 6.1.0. (not 6.0.1 or the current 6.0.2) but untill
I see someone on my network with 6.1.0 saying its fixed I'll be truly happy.