Move to a new certifier: names.nsf problem

I have recently created a set of CA certifiers for our company. I am moving our users to these certifiers and when I do the User Name field in the Domino Directory lists the users name with the new certifier 3 times in a row. Like this:

Test User/New OU/Acme

Test User/New OU/Acme

Test User/New OU/Acme

It doesn’t show the old certifier or the common name like it used to when I did a certifier change, which was something like this:

Test User/New OU/Acme

Test User/Old OU/Acme

Test User

Thanks for reading, any suggestions will be appreciated