Just fixed a customer with this problem by upgrading to 6.2.0.0-3.2.0.4. check the release notes for 3.2.0.4 under "Fixed Issues in this Release" -> Access Point Platform. To identify the issue addresses by this fix, ssh to an IAP and execute the comand show version. you will notice the reboot reason is master transitioned to local.
Dining_Hall_East# show version
Aruba Operating System Software.
ArubaOS (MODEL: 105), Version 6.2.0.0-3.2.0.2
Website: http://www.arubanetworks.com
Copyright (c) 2002-2013, Aruba Networks, Inc.
Compiled on 2013-02-15 at 22:20:03 PST (build 37229) by p4build
AP uptime is 26 minutes 58 seconds
Reboot Time and Cause: master transitioned to local (from 6c:f3:7f:cb:dd:47 10.10.24.147)