I know this is a know issue, and has been for a couple of months. I have been struggling with this on my 645 Music, and it seems to be getting worse.
With the latest update (end oktober/beginning november), my watch started to time out after about 1km, and gets stuck on the Garmin logo (rectangle thing) when i push any buttons. Anyone else had similar issues? I was fine with it not getting the calibration correctly, as I figured this issue would at some point be fixed, but with the complete breakdown of the whole system after 1km it seems a little useless.
Also, when I upload my calibrated data to Strava it only shows the uncalibrated distance, even though the distance in the Garmin Connect app shows the calibrated one.