Here are some potential solutions to try when emails are marked as unread even though they have been read:

1. Check your Trash folder; emails may be getting sent there instead of the inbox.
2. Check a spam folder; emails may be getting sent there instead of the inbox.
3. Unsubscribe from emails that you don’t open anyway.
4. Make sure the inbox you are opening is the same inbox that you are sending emails from.
5. Check the settings of the email server; emails may be set to be archived once opened.