Food regression

So my babe isn’t sick no fever acting completely fine but maybe the last week he’s been uninterested in the last 2 oz of his bottle he normally takes in 6 oz a feeding every 4 hours now he gets super uninterested in his bottle right at the last 2 oz only eating 4 oz. I mean sometimes I can make him eat the full 6oz (but I feel like I’m forcing him).he seems to just get bored looking around moving spitting bottle out I don’t get it he’s almost 4 months he’s supposed to eat around 6 oz.. maybe it has to do with his 4 leap. Maybe teething is starting (he is drooling more) Is there even such a thing as food regression? Help moms! any idea why my little one seems to know longer care for his last 2oz