If a student makes multiple database entries, they will all show up in the Grade Me block as needing to be rated. No matter which one the teacher selects to rate, you wind up going to the first entry the student made, even when that entry has already been rated.

The fix is easy. Change line 154 in lib.php to:
$submissionlink .= '/mod/data/view.php?rid='.$submissionid.'&mode=single';
Instead of:
$submissionlink .= '/mod/data/view.php?d='.$submissionid.'&mode=single';

Changing to rid takes you to the actual record id that needs to be rated.