For more than one month, I can't see the tracks in the events uploaded to the group calendar by other members of the group. Of course, other members can't see the tracks I upload, obviously...
If I understand well, you are looking for the maps with tracks for activities of other members on the Group Calendar. Frankly told, as for the Group Calendar (BTW available only in Gamin Connect Web) I do not know whether it ever contained any member activities. It is designed more for group events such as races, workouts, etc. The activities of members are accessible on the first tab Activity Feed. In the GC Mobile app, you have to tap the activity to enter it, and then you can see al the detail, including the map with the track. In Garmin Connect Web, the maps are visible in the quick previews directly in the Activity Feed.
Thanks for your answer, but what I mean is that I can't see, in the group calendar, the tracks and details of the planned events uploaded by other members of the group
Are you really referring to Garmin Connect Mobile Android (that's the forum you are posting to)? There is no group calendar in the GCM app, as far as I can see, and I do not think it ever was there.
If you mean the Group Calendar in Garmin Connect Web, then the calendar does not show any tracks or details of planned events. It only shows the name of the planned event:
When you then click on the event, it opens a popup window showing some details, including a link to the Course (if it was included with the event, which is not mandatory). So if no popup window opens upon clicking the event, check your browser settings, and disable popup blockers for the domain connect.garmin.com, and also disable adblockers for that domain.
Of course I am referring to GCM. As I wrote in my first post, it doesn't work for more than one month, what means that before worked perfectly. In fact we used to share our club's routes calendar and sent the routes to the GPS through our mobiles.
The calendar works correctly through garmin's web page.