Session requests routed to wrong worker break user sessions

With load balancing across multiple instances, requests associated with a session ID may be routed to a different process than the one that originated them, breaking session continuity if sessions are not shared.

Configure session affinity (sticky sessions) in the load balancer to route session-bound requests to the originating process. Alternatively, store session data in a shared data store like Redis so any instance can handle any session. Review socket.io documentation for multi-node session handling.