Flags don't always go away

My 2 inboxes are empty but they still have flags seeming to show I have new unread mail. Is there aanything I can do?

The flags that show I hvae unread mail don’t always go away - they stay even when I empty my inboxes. Mac version 9.2.1841 (8deda8f).

Is there anything I can do?

See screen attachment.