It seems many of my older activities (2009) seem to be missing all their gpx/track info. They have the totals on the left, but no track data in the map. When I export them as GPX or TCX they do have all the track info.
Some examples:
http://connect.garmin.com/activity/13861352
http://connect.garmin.com/activity/13861387
I've emailed support, but was wondering if anyone else had seen this...