I have set up an email workflow to notify me when an email is opened, that works fine.  

However, I set one up to check for unopened and it does not work?

Done the same for unreplied and it does not work.

Using the same lead record for the test which uses a gmail account

Anything obvious?  I am using POP3 does that make a difference?

An Update:  Created another lead which uses my default Zoho email address and the workflow does not pick up when the email is opened?  Does not show in Zoho lead screen either under emails.