[Samba] Samba 4 not honoring setgid

[Ryan Bair]

I'm running Samba 4.0.7 on CentOS 6.4 as a AD DC with s3fs.

I have a shared directory with the setgid bit set. From the shell on the
server, new files and directories inherit the group as expected. However,
new items created through samba get the user's primary group instead.

Config for the share is super simple:

[test]
        path = /srv/test
        read only = no


Sounds like a bug. Has any one else experienced this?