Description of problem:

Commit https://github.com/ovn-kubernetes/ovn-kubernetes/commit/27d1fb56852b837d863d5db30f7b538101fd06b6 introduced as temporary workaround a new NAT rule to SNAT all join-ip traffic to the gateway router IP.

That was to avoid the issue reported in https://issues.redhat.com/browse/FDP-159.

FDP-159 has been fixed in core OVN, the fix was released in FDP and was already consumed by OpenShift (and upstream):

https://github.com/openshift/ovn-kubernetes/pull/2066

It's time to remove the temporary workaround in ovn-kubernetes:

https://github.com/ovn-kubernetes/ovn-kubernetes/blob/0b2ed71ea0b3ea3f1da7b7c4fadf50cb8fd455dc/go-controller/pkg/ovn/gateway.go#L764

Additional info: an e2e should probably be added to cover this case.