New 2015 rMBP spontaneously restarted upon login. Causes?

[Hypnosis]

Just happened a few minutes ago. I got this rMBP a week ago, and after logging in, it went back to the startup Apple logo (it just restarted on its own). After the Apple logo appeared, it automatically went back to the "password login field" -- in absence of better words -- and after logging in the second time, there was no message or crashlog. Nothing. It booted up fine and there seems to be nothing wrong as I'm typing this. Any idea on cause? Should I be worried?

 

[T5BRICK]

Mine has done that once or twice. It doesn't happen consistently, I'm not sure what causes it.

 

[virginblue4]

Mine also does this every so often. Again, not sure why, seems completely random.

 

[yukari]

Mine used to do that almost all the time after upgrading to Yosemite. I then clean installed Yosemite and the problem went away.

Others have suggested it might be due to File Vault.

 

[Traverse]

Cause? Yosemite.

I get that on my 15" all the time. What's even more annoying is when I "RESTART" and it doesn't come back on. Then I have to unplug 5 cables and take it out of it's vertical bookarc stand to turn it on.

GET IT TOGETHER Apple! It really infuriates me. Don't make me wait until El Capitan in October to get a proper system.