Route using the wrong cached directions.

Thanks for replying.
Already did all the options (including empty the folders, reset,...), non works for me.

I have calculating off, so I do not expect the track not to go beserk when I take a wrong street 10m shorter or further on the track, it should do nothing that moment.

All strange, only other thing I can suggest is the latest maps, you never know. 

I did that too 

aweatherall what is the function / relationships of the files in Calcs and those in PointCache?

If I delete everything in all three directories and then load some courses (usually via "send to device" in Garmin Connect (web) I end up with a file for each course in Courses, Calcs and PointCache immediately, without loading, riding, "calculating". I have Turn Guidance disabled always. But I still get Ghost Courses randomly and fairly infrequently but always with TG off?

I have found the Turn Guidance switch can be reset to "On" by loading new software versions and various resets so it is worthwhile re-checking before big rides.

PS If I select the Course "Remove from Cache" option it immediately recreates a cache file in the "Calcs" directory but not the "PointCache",  I assume if a Turn Guidance "calculating" process then occurs there is some addition to the cache files but I believe there is something very wrong with the "cache" processing on the XX40 devices that did not occur with the cache process on the XX30 devices

It's not all that negative... On my Edge Explore 2, with similar pointcache logic as the 1040, I could kill the ghost course just by doing what you describe above. Note that I have Turn Guidance (TBT) ON.
The normal routine:
- Switch on device and wait for GPS fix
- Load my course from the COURSES list & press 'Ride' (decline Navigate to the beginning of the course) & start the timer  and begin cycling
- Then Oeps... there is the ghost magenta course line with the chevrons, apparently from an earlier ride or whatever - what to do?
- While underway now, stop the course
- Select the course and go to 'Route Calculation' (3 dots menu) which shows 'Cached'
- Tap on the Course and select 'Remove from cache'
- Now select 'Ride' and a 'Calculating' progressing percentage is shown
- When at 100% you can restart navigation (Not to the beginning of the course).
- Everything normal now with only the newly calculated course line with the chevrons. No ghosts anymore.

Thanks, I'll try this out next time I am out on a course and see a ghost route. I have TBT off, but hopefully it will still work.

I like to think that if everyone was having the same problem, it would be pretty high on Garmin's priority list. But without knowing the internals of how the OS and the feature are written, we can only guess. For all we know, it could be dependent on the wind direction.

What I find a lot more puzzling is how they can introduce such a bug, when the execution path (other than UI rendering) should be near identical to the code that runs on the 1030, yet it appears this bug is nowhere to be seen on the Edge 1030 or Edge 1030 plus. This is a bit more alarming, since it suggest a poor software design and/or architecture, and doesn't bode well for the future. And if it's a bug on the UI rendering, it should be relatively easy to squash.

All speculation on my part, I have no knowledge of how the software is written, nor how the team behind it works (or how under-resourced they may be)