Seems that the mapping of GTFS’ ‘route_short_name’ to OSM’s ‘ref’ does not work.
I’ve created the SMART Routes from the GTFS.
Please check the ‘ref’ in the SMART Routes and fix. I don’t have local knowledge.
Edit: changed ‘route_id’ to ‘route_short_name’
Edit2: That seems to be a bug in the GTFS data though.