The "next" link at the bottom of the modmail page doesn't point to the correct page

Just now the bottom of the first page of my modmail was an exchange where the most recent message was sent 8 hours ago. When I click "next" to view older messages, a page loads where the most recent message displayed is 18 hours old. However, I definitely received modmail in that 10 hour gap, and those messages were not displayed on either the first or second page of my modmail. I confirmed this by changing my preferences to display more links and loading my modmail again.