Hi @MargaretMoore
I was just investigating this behavior for one of our faculty members. It looks to me like it's an issue with the right panel on Speedgrader not updating all fields--the WC field in particular--when moving from one student to the next.
When viewing the Speedgrader panel for a student with no submission, we noticed that Speedgrader still showed a word count. However, it matched the word count for the first student displayed in the Speedgrader roster. So, it seems that Speedgrader was still displaying the word count value for the submission that was shown when we just opened Speedgrader for the assignment.