dhcp option new_rfc3442_classless_static_routes breaks routing

[jonakarl]

When the dhcp option new_rfc3442_classless_static_routes" is set, routing is handled by this script: /etc/dhcp/dhclient-exit-hooks.d/rfc3442-classless-routes
 
Without the multihomed-routing script the default route works so I guess something in multihomed-routing is interfering with what is later configured in / rfc3442-classless-routes (cluesless to what though). Alternativley some code must be added to rfc3442-classless-routes to setup the routes in the same way as in multihomed-routing (respecting the routes given by dhcp).