BuddyPress.org

Update:

There are 2 places in the WPMU Dashboard an admin can add a new user. Further up in the Site Admin>Users menu, and further down in Users>Add New. Welcome Pack is only activated if a user is added from the Users>Add New menu. And as mentioned above, that is where the glitch occurs.

In testing more thoroughly found the WPMU notifications work fine from both places in the Dashboard when BuddyPress is disabled. When BuddyPress is active the “Add New User” in WPMU develops the glitch as described above.