Weird Unity Ink Compiler Issue (Unity 2018.3 beta, macOS only)

I see this error logged in the console:

"Unhandled error(s) occurred compiling Ink file 'Assets/Ink/MainStory.ink'! Please report following error(s) as a bug:"

(nothing is listed below this)

This occurs about 90% of the time when the Unity plugin tries to compile our ink file.

If I select the ink file and keep mashing the "Compile" button, it eventually works. (no error message)

Using the latest Unity 2018.3 beta on macOS with the latest Unity ink integration. Doesn't seem to happen on Windows.