Node-red-contrib-aws-iot-hub 0.1.14 Only one instance of "aws-mqtt-in" works

I have installed node-red-contrib-aws-iot-hub 0.1.14
on
node-red v2.2.2 and node.js v12.22.12

I can connect to an AWS MQTT broker
I can send and receive MQTT messages via "aws-mqtt out" and"aws-mqtt in"

However, if I have several instances of "aws-mqtt in" defined, only one instance will work, all others will show "subscribing... " and will not receive any messages.

If I disable the working instance of "aws-mqtt in" another instance will start working.

How to diagnose this?