If a card is denied by card, then that means that the controller does not have that card in it's database. When this occurs, the driver will then check the host and if that card exists it will download it to the controller automatically. The controller that did not have an updated copy of the personnel database, but after a couple reads the update was sent from the host. This issue could be caused by several things one being if there was a disconnect in the network for a period of time while the update and/or a personnel download was being made and/or if the controller was reset while disconnected from the host. Perform a personnel download to the controller, just so that it is in sync with the host database.