User search in group/manage group/ members

I was going to change the permission role for a group member (Manage Group/Members). When I search for the user to change the permissions, she can't be found. 

However, she is a member of the group based on role, and if I choose to add her and search there, she does show up with the message that she is already a member.

It looks  like this is happening with many users, now  that I'm experimenting with it, but all  based on site  role. The group is set to Public (Open Membership) but the Telligent site role Registered Users is added to it as a Member. Any insight on why this  is happening?