Generic vs name brand formula

Anyone else notice their LO having stomach issues with generic formula? We have her in enfamil gentle ease and bought the generic due to price. Everything was ok for the first week and now she's back to spitting up large amount and crying while feeding which she did before we even started gentle ease. I read online that some people found generic to be thinner hence causing babies to be gassier and spit up more. Just looking for more in sight.