Routing Anomaly in Spain

Hi - I have been scratching around recently looking at various routing websites / apps and testing them on a known ride near where I live in Conil, Cadiz. The attached screen shot shows the start & end points of a cycling track from Chiclana to San Fernando; it's gravel, vehicles can use it to the bridge but it is ride-able on any bike except a perhaps road / racing bike.CT will not show the direct route but all other websites will including Google maps. Is this an OSM bug, a CT problem or a Spanish problem? Thanks