The specification should promote the interoperability of the main actors taking part in the communication - exchanging messages. This state machine is not related to communication between Publisher and Subscribers, but it is related to local state management of something (PubSub Component ?), for example, PubSub Application instance as one whole, but it is not stated and this scenario is not very useful in practice. This state machine could be applied to Publisher/Subscriber, but the application instance could create many publishers and subscribers at the same time ?!

We can ask what is the impact on the Publisher/Subscriber interoperability if someone will implement different state machine or there will be no state machine at all - always on. How to test interoperability?

The state machine may be used by the configuration services Client/Server interoperability, so it should be moved to the configuration service model in section 9.