regurgitate happens when babies drink too much milk as their tummies are still small. You can try to cut down on his/ her milk or give your baby milk at a later timing. It can also happen because we never burp them too which you’ve mentioned you did this. it could also be due to the way we carry them after they had their milk. Try not to jiggle them after they just finish their milk. Always position them upright. From what i know cold wind blowing towards them after their feeding too will make babies regurgitate or vomit out their milk. Do adjust the aircon or fan speed.
Regurgitation happens commonly. But different babies also have different volumes of milk their stomachs can take. Perhaps cut down on the volume that you give per feed, and feed more frequently for now. You can also try burping after feeding every ~30ml.
Cherlyn