Possible incorrect activity flagged in Marketo?

[Anonymous]

One of our sales reps followed up (via Outlook) with a lead that opened yesterday's email blast (according to Marketo, this lead opened the email). The sales rep received an autoreply email back that said "the person you are attempting to reach is no longer associated with X Company". How could the lead have opened the email if they aren't even working at the company anymore and have an autoreply set up? Is it possible that Marketo incorrectly flagged this open? Has anyone expereienced this before? Any insight would be helpful!

[Dan_Stevens_]

"Opens" are such an unreliable metric these days, that we don't even consider them in our metrics reporting.  Even "clicks" are sometimes done by email servers - where each link is click on to determine if it's legit and/or if there are too many links (which can often raise spam flags) before the email is even delivered to a users inbox.  This could also trigger a false open.

[Anonymous]

The person you are trying to contact that is no longer with the company probably now has an email FWD set up to their supervisor and that person may have opened the email.

[Anonymous]

Thank you both for your help!