I am using Vernemq MQTT broker with node-red both running in Docker in a Traefik Stack (though I don't expect that is the problem). I am seeing a strange symptom with repeated messages when subscribing to a topic. If I have a simple flow as in the one below with an inject node publishing a topic via MQTT Out node and an MQTT In node picking up that topic then all is well. However if I add a second MQTT In node subscribing to the topic with the last element replaced by # then I see two received messages (from the first MQTT In node) for each Inject. In this example the first topic is tydwr/testit/xxx and to make it repeat I additionally subscribe to tydwr/testit/#. Note that the additional subscription node is not connected to anything. If I delete the second subscription then the repeat stops.
Running mosquitto_sub at the same time does not see any repeat.
Using the same flow, just changing the broker to a mosquitto broker removes the problem.
[{"id":"c20136d0.1ab618","type":"inject","z":"bdd7be38.d3b55","name":"","topic":"tydwr/testit/xxx","payload":"","payloadType":"date","repeat":"","crontab":"","once":false,"onceDelay":0.1,"x":297,"y":1003,"wires":[["4cbf2a29.a1d304"]]},{"id":"c6eba3b4.a73048","type":"debug","z":"bdd7be38.d3b55","name":"test","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"payload","targetType":"msg","x":487,"y":1085,"wires":[]},{"id":"4cbf2a29.a1d304","type":"mqtt out","z":"bdd7be38.d3b55","name":"","topic":"","qos":"1","retain":"false","broker":"bbdb09c8.d3d0a","x":509,"y":1002,"wires":[]},{"id":"49f76222.230f34","type":"mqtt in","z":"bdd7be38.d3b55","name":"","topic":"tydwr/testit/xxx","qos":"1","datatype":"auto","broker":"bbdb09c8.d3d0a","x":284,"y":1078,"wires":[["c6eba3b4.a73048"]]},{"id":"b8aa9ddb.2ce188","type":"mqtt in","z":"bdd7be38.d3b55","name":"","topic":"tydwr/testit/#","qos":"1","datatype":"auto","broker":"bbdb09c8.d3d0a","x":282,"y":1152,"wires":[[]]},{"id":"bbdb09c8.d3d0a","type":"mqtt-broker","z":"","name":"","broker":"x201-vps.local","port":"1883","clientid":"","usetls":false,"compatmode":false,"keepalive":"60","cleansession":true,"birthTopic":"","birthQos":"0","birthPayload":"","closeTopic":"","closeQos":"0","closePayload":"","willTopic":"","willQos":"0","willPayload":""}]