I have a tiny network with 2 R600s in Unleashed mode. Last night, I upgraded to the latest (126.96.36.199.339) that apparently came out about a week ago. Multiple times after that, I'm seeing "heartbeats lost" messages.
Looking at the switch ports, I'm not losing link - the last up/down of the links was the reboot after the upgrade.
Also weird is that this is a 2 AP setup, and there are reports for both APs. How does an AP lose a heartbeat from itself?