My lo likes to leave 30ml in every feeding too. I think it's the bottle pressure problem. He will only finish the whole bottle when he is extremely hungry in the midnight or I have to manually lossen the cap and tighten it back to release the pressure
That’s normal:) my LO’s milk intake dropped after she started solids too. Gradually we cut down on the number of milk feeds as the solid intake increased.. from 6-7 feeds a day to 4-5 feeds.
If her weight is normal, I think it's okay.
Maybe she is full from solid food