Sounds like he’s getting a chunk of his calories at night, thus not hungry for actual food come daytime. That would happen to us when we were exclusively bottle feeding but they get used to calories at certain times so you’ll need to choose one of the bottles and gently push it out further and further 10 min each time until it merges with a day time feed.
He might just be going through a sleep regression. He’s at that age for one. You usually just need to ride it out.