Minor Problem with Route loaded on Oregon 650

I've sent 2 routes to my Oregon 650. Using the device and selecting "Whereto" & "Route" both routes are shown. When selected, one route opens up with map and Green "Go" button as expected. The other does not open at all. If I go to "Route Planner" I can select the problem route, then "View Map" and the map and green "Go" button shows OK. I've tried deleting and saving again but this does not fix this anomaly. Any ideas why this happens?