Have I got this right? Strava live segments won’t work on a Garmin edge computer when you are following a course. That seems to be the case for my 530 but it doesn’t make any sense.

Not my experience, however it won’t show anything with a negative gradient as a safety feature, and if you have climb-pro switched on then it will default to that instead of an uphill segment.

Never worked while on a course on my 810 or 820

Does work on my Karoo 2.

Won’t work on anything for downhill segments as Strava is worried somebody will sue them after crashing.

I was aware of the no-downhill limitation and that’s fine. I don’t want to be looking at my Garmin on a descent anyway. But I had starred two (uphill) segments on courses that I did over the last couple of weeks but (despite having strava segments enabled) nothing happened on the display as I rode through them. They were recording and showed up on strava when the ride was uploaded, but nothing live. I thought it might be because they were on climbs and ClimbPro was active, but a bit of googling showed a number of people claiming that they don’t work at all if you are following a course, which seems a bit daft.