Now that I think about it perhaps the "walking" the course on my 830 is related to me having Recalculation disabled. I typically want to run a course exactly as plotted. If I do deviate from a course I'll manually rejoin it without the Garmin coming up with a way to rejoin the course that might skip large sections. Back with my 800 I recall being near the start of a 200 km brevet and it recalculated to send me directly to the finish skipping 180 km, which I chose to ignore.