Email - IMAP not working as intended

I have configured IMAP accounts in ERPNext. The problem is that it reads the mail when it receives it. I have the same account running on three devices and due to this I am missing my important mail.
This is not the way IMAP works. Is there some setting I need to change?
Thanks for the help.

Can you log in as Administarator and check the IMAP settings for the email account? See the email sync option.

The Email Sync Option on ERPNext is set to UNSEEN. Also, the mails sent from ERPNext are not visible in my sent folder of email clients.
Thanks for the help!