The number that is showing the pending edits to review is visible on top of the page, but it is not visible in the review page.
Looking closely, the number is shown, but the color is too similar to the background one.
The screenshot was taken after approving an edit, the following one shows what I see before approving a pending edit.
This is similar to Number of pending edits unreadable, but that report has been marked status-completed, and closed as too localized, while I am facing the issue again.
