Baby cutting back on formula?

The past couple of days my baby has not been drinking his whole bottle. He leaves an ounce or two left. He acts like he wants the bottle when I pull it away, but then he just bites down on the nipple and lets go of it turning his head away from the bottle then does all of this again until I just put the bottle away. Idk if he’s not eating as much because we are doing solids twice a day now or if it’s because he’s teething or because of something else? He’s 5 months now and seems to be acting normal I think. He just started talking and screaming a lot more now (he likes to hear himself lol) and has been pooping more than he used to but all stools look normal. Idk what’s going on!

Edit: he used to drink 40 oz of formula a day before solids. The past 2 days he’s been getting about 33-35 oz. So he’s still in the range for the ounces. I just remembered that his pediatrician did say he would eventually cut back on his own. It just worried me for a little bit lol.