The active calories are calculated incorrectly.
Actually, all the calories I gather cycling are counting a second time as walking. This error is made both in Garmin Connect as in Garmin Mobile.
For the Garmin devs: you can check this on my dashboard: https://connect.garmin.com/modern/dashboard/14855592
It might have something to do with this: I have to select the "Other" activity on my Vivosmart HR as cycling is not available, and then I change it to "Cycling" after it is synced.
(if anyone knows how to add the cycling activity to a vivosmart HR, this would make me very happy).