How did you install it?
I was looking into the spec of the plugin, and if you use logstash-plugin install logstash-input-mqtt, it will install this one, which is not the one I linked in a previous post.
But this plugin also does not have an update in years.
Since you said it is working in your production environment, what is the difference to your local environment? Is Logstash and the operating system in the same version?