One other suggestion would be to test this in your environment. (Since I am not able to reproduce locally may be it would make sense to test it in your environment)
Can you comment this check in the 'rpc.py'(#L327, #L328 and #L329) and restart the service.
You may see an ERROR log in the openvswith log that is being added for DVR routers, but it should not affect the functionality.
One other suggestion would be to test this in your environment. (Since I am not able to reproduce locally may be it would make sense to test it in your environment)
https:/ /github. com/openstack/ neutron/ blob/master/ neutron/ plugins/ ml2/rpc. py#L327
Can you comment this check in the 'rpc.py'(#L327, #L328 and #L329) and restart the service.
You may see an ERROR log in the openvswith log that is being added for DVR routers, but it should not affect the functionality.