Notifications and re-invite

Hi I have a weird question. I have the EX2 Ultra running not issues. I have created users and shares (no groups) and everything works great since they update to OS5. I noticed the users in Mycloud no longer has the option to re-invite. That icon is completely missing. So the only way to do it was to delete the user and set them up again. This worked, but then the other users received and email saying the user had joined MyCloudEX2 Ultra and has access to the authorized share folders. Yet in notifications the only one email in there is me? Is there a reason why other users would get this email? And more importantly can I stop it?