Has the calories calculation been changed in Instinct firmware 11.18?

It appears that since the firmware update, the watch reports less total calories than before.

Because of this, the BMR formula previously used in my app is no longer accurate and the resulting active calories are much lower than those shown in Garmin Connect.

So the question is - is this a bug or a deliberate correction on Instincts?

And if it is deliberate, will it happen on all other devices?