Rabbit won't eat before bed sometimes

A couple times now one of my rabbits would not eat in front of me at night. No favorite treats, no pellets and just running away when I get near. His brother happy to get all of the pellets lol. But both times he started eating without issue in the morning. Has this happened to others? Is it just a tummy ache or does he get grumpy with me sometimes? It scared me alot both times thinking I'd have to take him to a vet when they open. They are both 9 months and neutered. Still semi new at a couple months with me. Photo for tax!

Fufu is a very silly lil boy

positive first rebonding session!!

first rebonding session went well today!! Merry nipped Pippin a couple of times, but never in an aggressive way, only in a "get out of my way" way🤣 we didn't have any grooming but that's okay for a first session.. but they didn't chase at all! and they've been flopping and loafing really close together🥰