Venue 11 Pro 5130 shutting down by itself with the keyboard with integratede battery

Hi,

I got a Dell Venue 11 Pro 5130 with my school in August. A little time ago, I noticed that when I move the tablet with the keyboard connected, it shuts down by itself. It never happen when it's plugged. I asked my school for help but they don't know how to fix it. They changed the keyboard connectors and the motherboard and nothing changes. I reinstalled Windows 8.1 and nothing happened either. I also noticed that the same thing happend to my classmates frequently.

Thanks