Hello. The same problem kept happening to me. It happened for a couple months and then, one month before the warranty ran out (amid rumors of an Android update that never came) it stopped happening.
Thus, I thought it was a software problem that had resolved after some update, but one month after the warranty ran out it began rebooting again, mostly while doing things that required more power and when the battery was around 60%.
I noticed the battery took extremely long to discharge, and any attempt to discharge the tablet while running would result in a reboot. So I left it on and unplugged while in firmware download mode (power on + vol down) and it recalibrated itself to show the real life of the battery.
Regardless, the tablet kept rebooting. So I rooted it and installed Cyanogenmod 13, then went to 12 because of BT issues. With both systems the laptop would reboot as well.
Until the day I found it just wouldn't boot. Not even charge (I connected it and neither the charger not the tablet heated up). Only then I decided to open it, disconnected and reconnected the battery cables. It started again and hasn't rebooted since (it's been only a few days, so I'll have to test it a bit more).