That is because the sensor did not get the initial setup downlink packet.
In your previous message your are seeing application data. So the sensor is sends data which is received by the network. It not being received by Node-Red probably means your MQTT setup (in node red) is not accessing the same application. Check your node-red configuration.
For the MQTT command-line subscription, the correct topic is ‘+/devices/+/up’, you also need to supply username and password to connect.
The device ID you need to enter in rs1xx-demo-config.json is the name of the node as entered in the TTN console. So if you call the node ‘sensor1’, the file should be:
{"dev_ids":["sensor1"], "degreesFahrenheit": true}
Read this message.
BTW Lairdtech is aware of the issue with the confirmed uplinks, it will be fixed in a future firmware release.
Perhaps ask the author of that message?