Not sure when it was fixed, but looks OK in Quantal (that bug is still open in Debian, but that can be followed in their tracker).
$ ls -l /usr/bin/at -rwsr-sr-x 1 daemon daemon 55480 Jun 11 10:03 /usr/bin/at
ii at 3.1.13-2ubuntu amd64 Delayed job execution and batch processing
Not sure when it was fixed, but looks OK in Quantal (that bug is still open in Debian, but that can be followed in their tracker).
$ ls -l /usr/bin/at
-rwsr-sr-x 1 daemon daemon 55480 Jun 11 10:03 /usr/bin/at
ii at 3.1.13-2ubuntu amd64 Delayed job execution and batch processing