So my 11" MBA has started to do something strange. Sometimes when video is playing, or some other macOS graphical thing happens, I get strange white horizontal lines... something that I can best describe as interference. It tends to go away, but it is noticeable and slightly annoying. I ran the Apple Hardware Test on startup and no issues came up. I can recreate the white lines when using a wireless mouse and moving the mouse a lot. The white lines are pretty consistent when I move the mouse, and tend to go away when I stop the mouse. I usually see this when I connect the mac to a tv with DisplayPort to HDMI adapter. When I record the screen, the white horizontal interference lines aren't recorded when I do a quicktime screen recording. I just recently updated to 10.12.4... so maybe it's a software thing. It's only on video though. Could it be the graphics system is on the fritz? Is it just interference. Searching about this problem doesn't come up with much, especially since it only happens on the video, not during general os use.