Milk

You may wanna take note if this is frequent? Because sometimes could be that baby is drinking too fast or over fed. Do pause feeding and burp whenever possible during interval :)

Sometimes it's phlegm. For my case my baby only vomit when she got phlegm ant I always check the vomit it sound gross no choice. Haha

Do check if it’s due to baby having allergies from BM due to what you have eaten.

Yes it’s becoz of phlegm .. better u mix more water if u r using fm means

Try to hold baby in an upright position after feeding

Possible, happened to my boy