This is something you could obviously do quite happily and for many was the reason why they upgraded to the 810. I think 510 users and others devices are also suffering the same fate.
I believe that the app was updated supposedly to counter this problem, however it still exists. I have just updated the firmware on the 810 to version 4.20 along with the 'Garmin Express' desktop software and was hopeful that normal service would be resumed, however I can report that for me at least there is no change. 'Upload Failed' is the message displayed every time I try to sync!
This also means that the 'Livetrack' function also does not work. If I want to upload a ride I have to plug the 810 into my Mac and sync the old fashioned way.
This does lead me to think yet again about the need for a Garmin 810 at all!? I mean, for navigation I have yet to find something as good as Google Maps, which offers turn by turn directions and more importantly voice commands. In addition all the data gathered from the 810 can gained from all manner of cycling apps. So, come on Garmin or you just might find me using my iPhone from now on...