Comment 4 for bug 1847203

Thx Lars for details.
It seems for me that those routers are either not added to queue here:
https://github.com/openstack/neutron/blob/1c2e10f8595d2286bd9bec513bc5a346a84a6f7c/neutron/agent/l3/agent.py#L574
either not returned from each_update_to_next_resource() here:
https://github.com/openstack/neutron/blob/ad028b55cafd74c39b1eb0708dba45a6fcfff059/neutron/agent/common/resource_processing_queue.py#L171 - as routers returned from this method are processed in https://github.com/openstack/neutron/blob/1c2e10f8595d2286bd9bec513bc5a346a84a6f7c/neutron/agent/l3/agent.py#L671

Can You maybe add some additional debug messages on Your env to check exactly where it is "stopped"?