Why do writes from docker container to shared volume not show up on host?

Using a docker-compose file with the local directory shared from the host, but files written on the container are not appearing on the host file-system. As a shared volume, shouldn’t files written out on the container appear on the host? Permissions seem fine and the file is reported to be written out, but it just doesn’t appear on the host file-system. Are there any good docker tools for figuring out what is going on?

More info: This is using docker-toolbox on OS-X, running under the /Users directory. Volume is shared in a docker-compose file and the command being used is from Django makemigrations. The source files are in the shared-volume and the migrations say they are writing out correctly, but the files never appear in the directory on the host.

As I understand it, as a shared volume both reads-and writes should be reflected on both the container and the host?