git > 2.10.1 fails to update index on macOS 10.14.5

After upgrading my work station, I found in git-2.22 that git would not 
recognize any file changes until I ran  `git reset --hard`. I thought 
that it was a problem with my own settings.
	However I upgraded to git-2.25, and the problem actually got worse. In 
2.25 the index still failed to update, but `git reset --hard` no longer 
had any effect.

I have not looked to find exactly where the breaking change was introduced, but I have since downgraded to git-2.10.1 and now get the expected behavior.