After looking at this a bit longer I believe I see what's happening.
Section 3.1.4 of the MQTT 5 specification states:
> If the ClientID represents a Client already connected to the Server, the
Server sends a DISCONNECT
> packet to the existing Client with Reason Code of 0x8E (Session taken
over)
Can you work up a reproducer that doesn't involve that operator?
For what it's worth, the terminology you used in your description seems
fundamentally ambiguous. You talk about "HA mode", "replicas", etc. This
terminology has a specific meaning in ActiveMQ Artemis and apparently a
different meanin
