Yeah lol,  if you're not impressed over a Dx1 you don't know what to look for. 
Anyway,  it is a glitch in the reading of the battery, it doesn't actually drop that much.   It does the same thing on an extended battery, even 10% sometimes,  but I get 24-36 hours from my extended,  so no way am I dropping 10% in 1 minute.  
I have noticed,  after it reboots and shows the drop,  it will drop slower after that,  sometimes sticking at its current level for some time. 
Hopefully we'll see a software update to fix it.   If not. I really could care less since its not really using up my battery. 
Sent from the hand of zeus!