Using NR v3.0.2 I'm using a MQTT in Node and keep getting the messages received twice. It might be a trivial issue... tried changing the QOS from the default 0 to 2 but didn't change anything. Thought it was the broker but ruled it out as other clients just receive the message once. This is anno…

[image] Colin: I vaguely remember a bug like that It is a feature :wink: There is a technical reason under the hood that I try to explain below however, if you have a v5 capable broker, switching to v5 will avoid this issue. In as short a terms I can, the MQTT client provides single stream…

All other clients (Python, iOS MQTT tool) just get one message. My MQTT node subscribes to 'events/#' Let me try to upload the capture of the debug node: [NR-MQTTBug-Screenshot 2022-11-16 114320]

Interesting to notice that the _msgid: are different between the duplicates. Where is that ID created? By the node?

In case you ask, the MQTT in node looks like this: [NR-MQTTBug-2] and the debug node: [NR-MQTTBug-3]

how many subscriptions do you have and what are they? For example, I can see a subscription to events/# - is that all? or do you also subscribe to events/testIP? Once more question, what broker (what version broker) are you using?

@Steve-Mcl you got it! I had another node subscribed to events/testIP (it was on different flow!) As soon as I disable that flow I'm now seeing NO duplication. Can someone explain? The duplication doesn't seem correct to me because it originates from the same debug node... To answer you about t…

Do you mean that the second mqtt node was causing duplicated output from the first? I vaguely remember a bug like that. What version of node red are you using? Look at the bottom of the drop down menu in the editor.

Using NR v3.0.2 Do you mean that the second mqtt node was causing duplicated output from the first? That's exactly what I've been seeing, I realized because my database had all the entries coming from this node duplicated.

Show us how you have the broker node configured please. Also stop node red and start it again in a terminal and post the full startup output here, up to the point where a repeated debug output is seen.

Thanks @Steve-Mcl , that makes it clear! In any case, understanding this feature, I have a workaround and can continue using Node-RED for my deployment. Appreciate everyone that chimed-in this thread.

[image] Steve-Mcl: It is a feature I can't replicate the issue using [image] When I click the Inject I just get one message from each debug node. The config nodes are configured mqtt v3.1.1 [{"id":"e2fd254e9f4f9785","type":"mqtt in","z":"e8ef959d13de8230","name":"","topic":"abc/def","qos"…

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MQTT node - messages received twice!?

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MQTT node - messages received twice!?

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