We shouldn't rely on automated network policy management available by default in OSSM installation. This can lead to issue when there are other apps running in the cluster which shouldn't be part of the mesh. On top of that ODH handles network policy creation on its own.

https://docs.openshift.com/container-platform/4.12/service_mesh/v2x/ossm-traffic-manage.html#ossm-understanding-networkpolicy_traffic-management