Why does my computer hibernate when it sleeps?
Have you tried resetting the SMC?

Here’s what you do for your particular model of MacBook Pro:


Shut down your computer
Keep the power cable plugged in.
Press at the same time shiftoptioncontrol (on the left side of the keyboard) and the power button
Let go
Turn your computer back on with the power button.


You can read more info about this on Apple's article about when you might want to try an SMC reset: 


https://support.apple.com/en-us/HT201295