When setting up a business rule, a notification can be send to either users or groups.
Assigning a user as a target for email notifications works fine, an email is received by the user.
When assigning a group to the same business rule, containing the same single user, no email is received.
The user is listed as a member in the group (so he logged in once into MDS). The user is db_owner and the group was tested as both a security AD group as well as a distribution AD group.
This is happening in SQLServer 2012 SP3 (11.0.6020.0), no experience with earlier product versions.