# Inject node triggers automatically when MQTT device connects. Is this normal and expected behavior
**URL:** https://discourse.nodered.org/t/inject-node-triggers-automatically-when-mqtt-device-connects-is-this-normal-and-expected-behavior/13320
**Category:** General
**Created:** [15 July 2019 20:52 UTC](https://discourse.nodered.org/t/inject-node-triggers-automatically-when-mqtt-device-connects-is-this-normal-and-expected-behavior/13320 "2019-07-15T20:52:56Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@MattCohen](https://discourse.nodered.org/u/MattCohen)
#### Post date: [15 July 2019 20:52 UTC](https://discourse.nodered.org/t/inject-node-triggers-automatically-when-mqtt-device-connects-is-this-normal-and-expected-behavior/13320/1 "2019-07-15T20:52:56Z")
Hi,
I was pulling my hair out with a small ESP32 device that seemed to be occasionally entering a state unexpectedly. After several hours of debugging I found that as the device came online it received several messages from node red from nodes I had wired up for testing previously. These nodes were just inject nodes connected directly to MQTT output nodes.
Is this the expected behavior. It doesn't seem right to me.
I am keen to understand why this would be happening.
Thanks in Advance
Matt
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### Author:  [@knolleary](https://discourse.nodered.org/u/knolleary)
#### Post date: [15 July 2019 20:56 UTC](https://discourse.nodered.org/t/inject-node-triggers-automatically-when-mqtt-device-connects-is-this-normal-and-expected-behavior/13320/2 "2019-07-15T20:56:24Z")
Hi @MattCohen,
it sounds like you have some retained messages published to the topics your device is subscribing to.
This will cause the broker to resend them whenever the device connects and subscribes - this isn't Node-RED's doing.
You can clear retained messages by publishing another retained message with an empty payload to those same topics.
[https://www.hivemq.com/blog/mqtt-essentials-part-8-retained-messages/](https://www.hivemq.com/blog/mqtt-essentials-part-8-retained-messages/)