I've used up my 20 "review pending edits" for the day.
I see an error that I'd like to fix -- which I can do without review -- but there is a pending edit on the question. The engine locks me out from editing that question, telling me I've used up my edit reviews for the day.
I can still edit to my heart's content on other questions without pending edits, though.
Bug? By design?
EDIT: I clicked on the Edit link from the main question's page. I did not run across this question in the review queue. I didn't see an "Improve" link at all, but I might have missed it.