22 unread emails, mailbox empty when I open it

OK I'm stumped.

One of my emails ported to my iPhone is showing 22 unread messages but when I open the mailbox it's completely blank.

Checked the trash - nothing.

this is a xxxxx.com address so I went to the server directly, checked the email there and it is NOT showing 22 unread anything. All normal there.

I turned off the account in the phone, waited a day and turned it back on. Nothing. Still the same.

I tested by sending myself an email from a different account hoping it would push the mystery emails to the open. Nope. Just the new test mail came through.

Hard reboot of the phone and syncing did nothing.

The apple mail server on my iMac is not doing this. All is normal there.

I loathe deleting the account in it's entirety and reinstalling into the phone because of all the time it's going to cost me deleting all those old emails that are going to come through again. Apple needs a "check all" button for deleting emails out of the phones.

Deleting the account in it's entirety off the phone, sycing, then reinstalling the account resolved the issues.

I almost didn't post this but I figure I would in case anyone else has this weird issue. Moderators feel free to delete if you want.