Hi @MelT,
This is a default behavior in the debug mode, irrespective of the environment.
Rasa uses a ticket lock mechanism to ensure that incoming messages for a given conversation ID are processed in the right order, and locks conversations while messages are actively processed. This means multiple Rasa servers can be run in parallel as replicated services, and clients do not necessarily need to address the same node when sending messages for a given conversation ID. You can read more about it in Lock stores.