REVIEW: http://review.gluster.org/5336 (system/posix-acl: normalize acl xattr before setting) posted (#1) for review on master by Raghavendra Talur (rtalur)
The latest build of vfs_plugin from Jose on 25th July 2013 fixed this.
As of the current date, the original patch was rejected by the Samba Team, but a new patch has been submitted to Samba Master for review. If the new patch is accepted, it must be backported to forge.gluster.org.
This is going to be fixed in samba upstream (plugin). We don't need a GlusterFS upstream bug.