Notification if email is sent to an invalid address

There is no notification from Clarizen when an email is sent via Clarizen and the address is invalid.
I tested and from Outlook I had an immediate answer but from within Clarizen, nothing happen and there is no notification.
Support team confirmed that is is not a bug but a feature .
It is very important to be aware of such problem, please consider this in your roadmap.

Thanks Fabienne