Customer has two emails; one from yahoo. When incoming from Yahoo, an Incident gets created but the outgoing email notification is getting sent to Internal Services rather than the customer.
On Incident there is a Trigger Action called ForNewIncidentNotification.
The Trigger Action is triggered on Insert of Object.
The Email Inbox Configuration is set to use method 2 and create record when Custom BO exists, using relationship IncidentAssociatedCustomer
When this Inbox option is selected, the Incident is inserted with ProfileLink = Internal Services.
The Incident is then updated to use the Custom BO identified through the selected relationship.
The solution is to update the Trigger Action to trigger on Initialize and Update of field ProfileLink_RecID.
You can also add a Conditional Expression to prevent email being sent to Internal Services.