I was tweeking the UI on the user admin pages today. I don't know exactly how your behavior occured but I did fix a bug where if a user was in state "requires approval" they were counted in the dotlrn/admin/users pending count but didn't show up in the list of users.
Modify users-chunck-small(etc) select_non_dotlrn_users and remove:
and membership_rels.member_state = 'approved'
The bigger concept here is that a person can be a registered user of the system without being a dotLRN user. But to actually do anything at all with dotLRN as it is at this moment you must be both.
Someday, this difference will be usefull but right now the UI is a bit difficult.
I am trying to make it easier for Sloan by adding a one-click approve and add to dotLRN.