Incorrect Total Ascent on Garmin Edge 820 after latest update

I recently noticed this problem: while the altimeter is working fine, showing the correct altitude, the Total Ascent of the ride is very incorrect. It's adding up much slowly than it is supposed to be, or not adding up at all on some steep sections. At the end of the ride, the Total Ascent is much lower than it is supposed to be.

For example, after climbing from 700 meters to 1700 meters altitude, with some small descents in between, the Total Ascent was obviously supposed to be minimum 1000 meters, but it was only around 600 meters. The Total Ascent for the whole ride was 800 meters, while my friends had 1400-1500 meters (they also have Garmin Edge, 820, 530, probably without the latest update). The same day, another ride with some steep climbs, same problem.

I think it's because of the latest update...

Please fix ASAP, this is totally wrong. 

  • Slope
    Garmin Garmin Elevation Fit Difference Fit from garmin
    Total Ascent Elevation
    2000 2223 2220 3
    2264 2507 2518 -11
    2498 2787 2782 5
    2500 2792 2784 8
    2659 2962 2963 -1
    2723 3032 3036 -4

    I did notice that the elevation updates are more often than the total Ascent .  The elevation with go up every few seconds on a climb, mostly in 1 ' increments, while the total Ascent updates every 30 seconds, in chunks of ~5-15', depending on grade, but that just results in the scatter from the fit as shown in the data above and wouldn't result in systematic 13% error.