I typically click on the "Last Modified (submission)" field to get a list of students who have not submitted their assignments - to both enter a 0 for the grade, and to get in touch with them to see what's going on.
Since the update to Moodle 2.8 from 2.6, I have noticed that some students have a date under that field, but nothing has been submitted. When I go to their log files for that time, all it says is "The status of the submission has been viewed.". That is causing a date of submission to be entered?!
I haven't had time to test it out, but has anyone else come across this? TIA