Groups in Mail [Mojave]

I am using Mail, Mojave etc - I have a group of roughly 25 people and all names and emails are just fine in the Contacts list for the group = but when I put the group name in BCC this is what I get == every name is there 2-3-4 times [even tho each one only has one email] - so I can't email to the group without going thru Contacts and pulling each out.