If there is no packet reaching the server, you will need to figure out if the agent is trying but being blocked by the DACL or it does not even try. Can you run packet capture on the client itself and see which is the case?
I don't think you have any control on which posture results are shown to the users. When everything passes, they shouldn't see the list unless the user clicks on the NAC agent icon. When something fails, the whole list is shown to the user for both pass and fail.