What are the access points using for initial discovery, and what is it pointing to? If it is using DNS, you can put two addresses in the A-record for Aruba-master so that not only will it try the local, but the master initially.
You could have the problem you describe if the initial discovery is only pointing to the local. The access point only gets the lms and backup lms-ip when it has successfully contacted a controller after a reboot. It still must contact an initial controller to get those two parameters. Putting in a second address for the a-record of aruba-master could help deal with that.