I’m seeing an issue where I’m getting duplicate uplink messages appearing in TTN (and to my MQTT subscription) when I have acknowledgements enabled. It doesn’t happen all the time, roughly 50% of messages are duplicated
You can see that the payload and fcnt are the same for several messages. What I suspect is happening is that the uplink is getting to the gateway, the gateway is sending the ACK back to the device to acknowledge receipt but the device is not receiving this and so decides to send it again. This is all totally understandable. What I don’t understand is why the network server isn’t seeing these messages as duplicates and doing it’s magic to remove them? Does the de-duplication only apply to messages sent at the same time and received by different gateways? I understand that use case but I’d still have thought that messages with the same payload and fcnt would also be de-duplicated.