My Garmin 310xt is failing to sync an activity every couple of weeks. I continue to keep plenty of memory on the watch by clearing out old activities. I have tried deleting all but the troubled activity, selecting "transfer all" and then syncing again. The activity still will not sync. I then perform another activity, and that one syncs fine. but the one before continues to fail. This has happened multiple times in the past few months. When it happens, I usually see in my history log on the watch that there are two activities set to "Today" when I am scrolling through history, even though I have only performed one activity that day. I will delete the bogus "today" activity and try again with the real one, but it still won't sync.
I have updated software, but it seems like this bug persists. What can be done?