Operating system: MacOS Mojave
Graphics card: NVIDIA GeForce GT 750M 2048 MB
Broken: 2.80 beta 2018-12-03
Worked: 2.80 beta 2018-11-30
When Launching the blender beta there seem to be two light grey bars on the top and bottom as highlighted in the first photo. It wasn't there in the previous version of the beta from a few days ago as shown in the second photo and looks a lot nicer without the grey lines.
The grey lines go away after resizing Blender.