OCP 4.18: after upgrade, Egress IP traffic flow is interrupted/failing intermittently.

Issue

• After an upgrade from an earlier version of Openshift (4.17 or lower), EgressIPs are inconsistently applied for traffic leaving the nodes.
• Some pods periodically NAT traffic from the local host node instead of the egressIP
• Traffic is intermittently dropped either due to firewall rules rejecting node traffic, or return path traffic sends to the wrong host (stale nats).
• Critically - An OVN-Kubernetes DB rebuild does NOT suffice to resolve the issue on affected egress-assignable nodes.