It looks like the plugin is not reconnecting when the connection to the MQTT server was lost. The MQTT server I'm using is a home automation server on the local network. I experienced this after a power loss and after a regular reboot of the server. Actor remains in the state it was before the MQTT server reboot and the sensor does not update until craftbeerpi has been rebooted. Result: fermenter (fridge) was at 5 degrees while craftbeerpi reported the target temperature. I'm still testing the setup, so no beers were lost :).