NPS Radius clients disappearing if multiple users are adding clients

Hi,

We have 2 network users that are in NPS adding radius clients at the same time as we have a lot of radius clients to add.  They both have the exact same permissions, however when one user adds radius clients, they disappear, the other user's additions do not. 

A) Is there a limit of how many users can add NPS clients at the same time?

B) Is there a limit of radius clients that can be added in Server 2012?

Thanks!