Ipad mini gen 1 reboots frequently

My Ipad gen 1 started to reboot frequently since the 9.3 upgrade. I have tried to make a factory reset twice to solve any possible configuration issues. The problem is there even if only the IOS standard sw is installed, ie no other apps are installed.

Seems like the problem only occurs when I communicate with the device.

I have looked into "Diagnostics & usage" but don't really know what to look for to get an idea what is causing the reboots. Any idea how to identify the problem cause?