Question
Inactivity filter vs. activity filter
I'm seeing a discrepancy in the number of leads when using "Email Opened 'is not'" vs "Not Opened Email" in one program. Why does this happen? If I want to send an invitation email to a list of people who did not open the email the first time I sent it, which filter do I use and why?
Smart List #1: (results = 405 leads)

Smart List #2: (results = 523 leads)

Thanks.