Member receives messages to old email address

We have a member who changed his email address a few months ago due to a change of jobs.
His email address on FTH was updated to his Gmail address.
However, emails sent to the Members email distribution list are still sent to his old address at his previous employer.
This is very strange because we can't find this old email address anywhere on FTH. See below screen capture from Member Management and the automated reply we still from the work email.

How can we verify that the address is updated in FTH?

Did he by any chance set up a secondary email address in his profile and ask for email to be sent to both addresses?

If so, and only one of those addresses got changed, that could be the explanation.

Thank you! I wasn't aware of the secondary email address! That must be the cause!