Mommies, good evening, we're having formula. For a week now I've notic…

Mommies, good evening, we're having formula. For a week now I've noticed an unpleasant stool smell in my son. It wasn't like that before. The smell is not sour, the child is active, there are no constipation or diarrhea, we go to the toilet normally 1-2 times a day. What could it be? Is this the digestive system starting to normalize its work?