It took me forever to get the polling of fan_action working. Essentially, I have to refresh the z-wave node for fan_action and hvac_action to be updated correctly. I ended up doing this with an automation script that refreshes the node every 30 seconds.
I also messed with a lot of other things to get this going. For instance, I noticed that configuration parameter 23 “Autosend Enable Bits” was not editable in the default z-wave setting for this device. I changed this in the z-wave XML file, to make this parameter editable and put it to 8319, as described here: homeseer forum. But it could be that this parameter was set correctly to begin with. At the end the refresh node was still needed.
By the way, I got the idea here: https://community.home-assistant.io/t/gocontrol-gc-tbz48-z-wave-thermostat-cant-control-setpoints/5404/16. But instead of zwave.refresh_entity, I chose zwave.refresh_node.