Dark Horizontal Lines on MacBook Pro Retina Display While I was using my MacBook Pro (Retina, 15-inch, Mid 2015) running 10.12.1 Sierra, dark horizontal lines popped up and the screen flickered a little. They turned off and on for a bit and I took 2 pictures while they were on and off. It's been 2 days and it hasn't turned off again. I restarted my computer by it's still there. Is this a hardware issue? What's going wrong here?

Top image has lines, bottom image is normal.
Apple just today released the macOS 10.12.2 update. If you have not already done so, check the App Store for this update and install it. 

Other general troubleshooting procedures are to reset the SMC, and also reset the NVRAM.

If the problem persists it would be good to know if the problem occurs both when running off of battery and when plugged into the charger. Also, if other peripherals are connected (displays, hard drives, etc.) does the problem occur when they are not connected?