When setting an expiration date for cardholders, that date passes, but the cardholder still has access.
One possible cause of this issue is that the ISC does not know to store the expiration date. Under "Access Control" and "Access Panels", select your access panel. Under the "Options" tab and in the "Store expiration and Activation date" option, make sure "Date Only" is selected for both options.
***Note*** This is performed in "System Administration".