I figured it out. We use UTMs at small remote sites for our Firwalls and routing. They build their own VPN tunnel back to our data center over a standard Cable or DSL ISP. The APs have trouble holding the GRE tunnels over UTMs and the tunnels break.
In this particular instance, the local AP would reach back to the master controller via DNS under the default profile. The master controller would give it it's AP Group and reboot the AP extablishing it's GRE tunnel and pointing it to a local LMS controller. The AP was having trouble establishing a GRE tunnel through the UTM and would revert back to the master controller.
Once I rebooted the UTM, all of the APs came back online.