What AOS version you have installed ? Do you have a 5.x code installed ?
It seems as that AP is bootstrapping .
Can you please run the following command to see if the AP is bootstrapping a lot:
(controller) #show ap debug counters ap-name test-ap
AP Counters
-----------
Name Group IP Address Configs Sent Configs Acked AP Boots Sent AP Boots Acked Bootstraps (Total) Reboots Crash
---- ----- ---------- ------------ ------------- ------------- -------------- ------------------ ------- -----
test-ap test-apgroup 10.66.8.64 598 596 0 0 1 (2 ) 2 N