Can you provide more information? From what you have said, if both wlc's are setup the same, I don't see why you would have this issue. One thing to remember is that when an ap moves from one wlc to another, it takes on the configuration of the new wlc. So if your wlan's are not in the same order, or if you are using wlan overrdie or ap groups, you must make sure that during a failover, the other wlc can support the function of the wlc that went down.