With the git source, the -X flag no-longer works. I suspect this problem was introduced fixing bug #5526.
For a simple test case try:
sudo mkdir /var2
sudo rsync -aX --link-dest=/var /var/. /var2/.
ls -laZ /var2
You should see that /var2 does not have the correct xattributes.
*** Bug 5539 has been marked as a duplicate of this bug. ***
This bug has been around since 3.0.0, so no, it's not recently introduced. I should have it fixed soon.
The fix for this was committed to the git repository, and is available in the most recently "nightly" tar file.