ipadOS 14 showing emails unread

Updating iPad to 14, old emails that show as read on Mac Catalina and iPhone 13.7 show as unread on iPad. How can I get the “read” status in sync on iPad without reading every single one of them? All three devices are IMAP so I would expect it to just work correctly. I don’t want to update iPhone to 14 until this works. Do I need to delete and recreate the email account on iPad (and then on iPhone)? Or will the same thing happen again? What an annoying bug! Thanks.