Its possible the TSTAT isnt getting the message. How far from the panel is the TSAT?
Have any changes been made to the environment? Adding/moving furniture appliances, mirrors etc. in the area? Were any Z-Wave devices removed from the network?
As a test, disarm the system then power cycle the panel. Leave it off for a couple minutes, then power it back up.
Once it has rebooted, wait about 5 minutes, then run a Z-Wave network rediscovery. Afterwards, test the rule for resolution.