Have you made any other changes to your Z-wave network? I would recommend running a network rediscovery to make sure the Z-wave network map is accurate and the device is using the best repeating route.
If you have already tried disabling and enabling the rule, and editing/resaving the rule, I would recommend deleting that thermostat from the panel, wait about 20 minutes, power cycle the thermostat then relearn it into the panel.