What is the logic that flags an incoming email as "Email appears to be a system generated message" ?
And can it be changed, or exceptions allowed?

We are trying to have a form on web page send an email to Service Desk to create a new incident.
However, the email gets flagged "Email appears to be a system generated message" and the incident does not get created.

Is it the fact that the From: address shows "[mailto:no-reply@blahblahblah.com]" ?
Sending the same message body to the same Service Desk email address from my email address does create a new incident.