One thing that I would investigate is that the internet connection had been lost. If your scour the Antminer S5 OP I seem to remember someone saying that their S5 fan slowed down after losing internet connection but the machine kept on running at full throttle to the point that if they had not been there watching it happen the machine world have burned up.
I do not know how you can prove that this happened in this case but if that did occur then you will have a warranty claim.
Also, scouring that OP, others have claimed that the 80°C fail-safe does not work either.
Chances are close to zero to get a warranty for this, as even Bitmain seems to know meanwhile whats up with ASICCRAP.
It was a necessary decision to move quick and void warranty or to leave things there and go the lengthy and probably unsuccessful route of claims and lies and more lies. ASICCRAP would have never handled the return process properly.