At start of course it is displayed correctly, but then disappears. The same effect occurs using the browse map facility, and shifting view to follow the course.
If I start navigation the course appears, and stays visible - but 1030 signals 'off course' whilst plotting my track exactly on my downloaded course
I design & download the course using TrackLogs & have OS map installed.
I used TrackLogs and the OS map this way with no problems on Garmin Edge 800 and 810