What has tech support said they saw in your logs? Everybody's AP connectivity issues should be able to be figured out by the AP support info, and a good network description.
Always being able to find the LAN's def-gw IP is important for stability in Unleashed, but otherwise, I can't explain any AP lost heartbeat disconnects from what we're saying.
Has anyone else opened a ticket and had their logs read? I'd like to know too...