The RH binaries use the ACL patch for backward compatibility with previous version of patched rsync

This is now fixed in the git repository.

This bug could also affect runs that did not use --link-dest:

If a file was transferred w/o any xattr changes, and a later file needed to update its xattrs to be the same as the earlier file, the receiver and the generator had different ideas about what was still abbreviated (and the receiver died with an error).

Thanks for the helpful test case!

I just tried a build from git.  It looks like xattr are not being copied at all now...

# rsync -aXHSA --delete --link-dest=/media/backups/hartnell.local/DellPrecision490/Fedora9/200806101037.dir /dev/shm/lvbackup/src/. /media/backups/hartnell.local/DellPrecision490/Fedora9/200806101248.dir/.
# ls -ladZ /media/backups/hartnell.local/DellPrecision490/Fedora9/200806101037.dir/var
drwxr-xr-x  root root system_u:object_r:var_t:s0       /media/backups/hartnell.local/DellPrecision490/Fedora9/200806101037.dir/var
# ls -ladZ /media/backups/hartnell.local/DellPrecision490/Fedora9/200806101248.dir/var
drwxr-xr-x  root root unconfined_u:object_r:default_t:s0 /media/backups/hartnell.local/DellPrecision490/Fedora9/200806101248.dir/var

I would reopen this, but it looks like I don't have sufficient privilege.

For a simple test case:

sudo mkdir /var2
sudo rsync -aX --link-dest=/var /var/. /var2/.
ls -laZ /var2

(Note that the immediately prior comments about the bug not being fixed were actually a different, old bug that was fixed in bug 5538.)