I usually walk to and form work every week day, and that has been showing about 40 active calories each way. That is also what my other activity tracker estimates. But since a few days ago (after I recall getting a new update) the active calories now is twice as high or about 100 calories. I also noticed that just walking a little bit inside increases active calories much quicker now.
To me it seems like a bug as the active calories are so high compared to what it used to be and what other actiivity trackers estimate.