Watch: Enduro 2
So the activity had almost 2h break in between the tracked activity. (only 16:09 min of which was tracked)
Issue is that the activity shows that I gained 105 minutes of "Vigorous intensity minutes" from this activity.
And it is definitely incorrect since in the non-tracked part of the activity, my HR was close to resting zone.
So there is most probably some incorrect calculation methods used for
determining intensity minutes based on "Elapsed Time" instead of tracked part of the activity.