I think I might know what it is, but I can’t reproduce it at the moment because I don’t have the full codebase handy on this computer. Could you try changing the /logout handler in guestbook.routes.services to set the session to an empty map instead of nil like so?

["/logout"
    {:post {:handler
            (fn [_]
              (->
               (response/ok)
               (assoc :session {})))}}]

I believe that setting it to nil is completely blowing away the ttl-memory-store so that we end up with a new session ID when we hit /login again, but the websocket still has the stale session ID.

If this is the problem, the “proper” way to solve it would be to keep the nil server-side, but to have the client refresh/redirect to / so that all client-side state is re-instantiated as well.