Not sure about formula but my breastfed baby gets all shades of green poo all the time! Showed them all to the PD and he said it's all normal. So unless baby shows discomfort it should be fine but doesn't hurt to take a photo and show PD
Green colour usually means something is wrong... do check this article https://sg.theasianparent.com/baby-poop-guide/
Hi... I’m not sure how deep is the green poop. I suggest you bring your baby to the PD
Jesslynn Ong