I'm using firmware 6.44.
I noticed yesterday that if I create a course from ride history on my garmin the timing ahead/behind works fine.
If I load a gpx file with timestamps in to the new files folder, I can navigate the course but I don't get time ahead or behind.
I opened the fit file created by my garmin and the issue appears to be in the header data. My garmin creates a field of "Course Capabilities" which is set to 515. This somehow prevents the use of course timing.
If I delete this entry then the course file works ok.
I'm not sure when this bug was introduced as I don't use courses all that often