Over the last year I have noticed several instances (usually after power outages) where a number of APs would show down on the master controller (GUI and CLI) but they would actually be up and working as intended. We've upgraded to the 6.1.3.4 code but that hasn't seemed to make a difference. As a quick fix, I usually just reboot the APs in question and they show back up on the master after they boot.
The APs that do this are mixed model and they're in no particular subnet, vlan, or groups. It seems to be fairly random. Our current model consists of two Local controllers that handle all of the AP terminations and one Master above them.
To clarify, this happens after the APs lose power during an outage and come back up, not the controllers.
Is there any way to force the Master controller to see these APs without rebooting them? I can ping these APs from the Master and I tried "clear gap-db ap-name XXXX" but that simply removed the down entries. This hasn't been causing any issues for the end-users but it can be a headache from the administrative side of things.