GroupRide Stats not displaying anything

I have used GroupRide with a friend a few times recently. We both have Edge 1050s and are both in firmware 29.22 (latest).

On the GroupRide page, the 'Riders' and 'Messages' tabs work as they always have, but the new 'Stats' tab doesn't show anything - see screenshot below. We are both using power meters, HRMs etc, but nothing ever shows up.

Has anyone got this to work? Is there a setting somewhere we've missed?