Depends on the controller model. Older hardware used to be susceptible to getting into a SNMP request spiral where if the request failed - AirWave would init a new request. This was why AMON was created to offload the need for polling with controller pushing the data to AirWave.
The error seems different though. It may warrant opening a support case or possibly a fresh install since typically when AP are added, they get an aruba_ap_group_id. Try checking the System -> Status page for the web server log (aka /var/log/httpd/error_log) to see if there's any crashes.