This is a long standing issue that hasn’t yet been addressed.
See the “Newly created inputs not appearing in emonCMS via MQTT” thread from around post 10/27.
The issue has been confirmed to only exist within emoncms MQTT implementation, all data can always be seen via mosquitto_sub which points to either the mqtt_service or more likely phpmqtt_input.php.
Agreed, but to date the only sure advice to overcome what has sadly become “expected behaviour” when adding new nodes on an emonPi/emonSD, is to reboot
However, in the “MQTT Strangeness” thread @TrystanLea confirms he had no issue having “only just started the mqtt service script” so it maybe that the emonPi doesn’t need a full reboot, I haven’t tested this theory yet.
As for restarting emonHub, that shouldn’t be necessary, emonhub was written to run continuously, it shouldn’t ever need restarting unless a revised version is installed/updated etc. All settings should be picked up during normal running.