Strange visual distortions in Mac Standalone when Resizable Windows enabled

I am experiencing visual distortions in my game in which straight lines in parts of the screen appear jagged or wavy due to horizontal tears across the screen. These "tears" are constant and not dependent on camera motion. This only happens when I launch the Mac standalone in fullscreen mode. Everything appears normally when I play the standalone in windowed mode at the same resolution, even after I maximize the window.

The images below are an example of the difference between windowed mode and fullscreen mode. No other settings including resolution are different between the two. Why is this happening??

EDIT: After some tinkering I have found that this only happens when Resizable Window is enabled in Player settings.

UPDATE: So I updated Unity to 5.6 and then i added this code to a script that runs on startup:

 if (Screen.fullScreen)
     Screen.SetResolution(Screen.currentResolution.width, Screen.currentResolution.height, true);

and now there are NO distortions in fullscreen mode, but NOW THEY APPEAR IN WINDOWED MODE. I tried to use similar code for windowed mode to no avail. Does Unity have a personal vendetta against me?

Normal background:

Background in fullscreen mode: