I have had a Garmin 520, 530 and now am using a 840, never had this issue before.
the problem is, I have Elapsed time as a data field on page 2 , but for some reason this seems to just do what it wants, if i start a ride at 8:30Am for example when I check at to see how long I've ben riding after around 2 hours I would expect to see a time of around 2 hours, but instead I often see something like 5 minutes but it is always different, sometimes it's ok sometimes theres a little number next to is and it's not right.
for some reason I opted into to the beta software when I got the 840, is this why it's not working? If so how do I get back to the normal software?