formula milk causes phlegm?

It’s true some baby get constipated, diarrhoea or phlegm when using certain formula, just need to make a switch slowly and not immediately. Maybe feed 4x a day, 1 x can use new formul and slowly move away from old formula. Then can judge whether the new one is suitable. Just donate (some people don’t mind) the old formula. Don’t save money because it is expensive as your baby health is so much more important.