I think I had the send early threshold set to attempted.
Admittedly I did not advertise this change, so I don't think there was enough awareness for other faculty to decide if they liked it or did not.
They just saw that grades weren't being passed back. My guess is that I changed owner/permissions on the webwork2.log file by mistake while upgrading to 2.20 and didn't realize that this had broken the job queue.
We use a daily mass update, and do not update on attempt, because IT thought it would create way too much traffic when you have 1000 students all trying to beat a homework deadline. A scenario that happens every single year is that a student completes their homewor, immediately checks Moodle, and then emails to complain when they don't see their grade updated...