Approval mailto: links are populated with the service account email address instead of the impersonated email address.
In Active Roles, if the Default Mail Settings properties are set to use Exchange Web Service (EWS) with Exchange and Modern Authentication enabled. If there is a different impersonated account being used other than the service account email, and the Send approval response by e-mail
option is selected.
The Approval links for Approve this request
and Reject this request
will display the Impersonated email address in the mailto: links instead of the Service Account email address.