Unity UI Tearing on resolution change on OSX

I'm working on a cross-platform Windows/OSX game, and I built and tested the UI on Windows (where it is working perfectly fine). When I run the game on OSX, however, the UI images have pixelated alpha regions in seemingly random places (see screenshot).

This only happens on particular UI elements, but I can't detect a pattern with which ones it will occur on. It is happening on both World Space and Screen Space canvases, from elements as complex as deep hierarchies with multiple canvas groups and masks to elements as simple as a single image.

This tearing only happens, however, when the resolution of the game is changed during play (including the "Maximize on Play" option in Editor). If you build the game and keep it at the default resolution or play in editor without maximizing, the tearing doesn't occur. I'm not a low-level programmer, but I have a hunch that it has to do with the stenciling that Masks use. Any help would be great.