[Q] Heartrate sensor works weird after lollipop upgrade topic

I recently upgraded galaxy S5's OS to lollipop.

After that the red led of heart rate sensor turns on every time when I place my finger (in device wake-up status) upon it even if I'm not using S-health application to check my heart rate.

Is it a bug or something about background recording heart rate?

Now I'm worrying about the battery consumption of it.