iPad shows I have unread messages when I don't have any

The Messages icon on my iPad has a flag showing I have 8 unread messages. I don't have any messages on the iPad. All have deleted from it. My iPhone and my iMac both correctly show no unread messages. How do I make the erroneous flag go away and correctly display only when I do have an unread message?

Using iPad Air running iOS 12.4.7