Agent determination problem

I have a function module that looks up a particular authority in the org structure and returns a list of users to receive a workitem. I've run this with different authorities and it returns a list of users and sends them all the workitem. This one particular authority returns a list of four users but only one receives the work item. When I look at the step and list the possible agents, I get the four that I expect but they look like this:

http://img219.imageshack.us/my.php?image=paul2wn2.jpg

The one with the inbox icon receives the item while the others do not. In the other tries where all users receive the item, they all have the icon. Is this some sort of security issue with these three users...they can't either run SBWP or they can't receive items because of permissions?

My function module seems to be returning the correct agents, the workflow step just can't route them anything.