please keep a watch and if it continues,consult yr doc once.

but I feed formula then I think there is no sense of foremilk and hind milk.

here is a blog u would find useful. please go through the link given below. https://www.parentune.com/parent-blog/green-potty-in-breastfed-formula-fed-babies-causes-coping-strategies/2938?ptref=sa0l00