Well since it's just a guess I would turn off all safeties if possible and try it again.

Just because you have a safety doesn't mean it might not be working right.

I would also run it slow to build up the heat slowly and see if it does it again. It could be that the ESC is internally very hot but the heat sink has yet to have the time to dissipate the heat?

If that doesn't work then I would think it has to be BFM. Black F'in Magic. If new time to get some warranty help