Redmine

Pre-condition:
I have a project with groups of people.
News added sends out notifications to all members of the project as expected.

Scenario:
When I add a new user to a group or to the project itself and they have an invalid email, email notifications fails to send to everyone, not just the user with the invalid email.
I believe it only acts this way when the email address that is "invalid" has a valid domain. I.E. when I have accounts with completely fake emails (e.g. asdgasd@asd.com) then the rest of the emails still sends out to the other members, however when I have an account that has a valid domain (e.g. fake@somerealdomain.com) then the emails fail to send as a whole.

I feel this is not how it should be, it should be able to send emails to the rest of the members, even if the email is invalid.