Hi,
A small voltage shock with no grounding could've wiped the RAM memory, maybe a spike in powering or just something stopped working with no reason.
These are really rare and there are too many factors to find the real cause of the issue.
But for safety's sake please try to find a way to keep an eye on power, if the voltage is stable and there's nothing that could shock the device.
Also, please update the device to the latest firmware, sometimes software could be the reason for these too.
EB.