This is an issue with the current iteration of Faster Docker Volumes for macOS. There’s been a bug with the built-in version of the NFS server (what FDV uses) on macOS since El Capitan.
One solution is to go to Settings » Advanced and disable FDV. However, I know that’s not ideal since it’ll drastically slow down Local sites.
With all of that said, we’re actually in the testing phase of Faster Docker Volumes version 2 on macOS. It doesn’t use the built-in version of macOS’s NFS server. There are several users who have tested it and it completely eliminated this issue with no side-effects that we’ve seen so far.
You can expect to see Local with FDVv2 sooner than later