My dog won’t eat during the day – only at night?

So I have a mix breed medium size puppy that's almost a year old. Throughout her lifetime, shes always got breakfast and dinner (and lunch when she was smaller). We have been consistently feeding her in the morning (9am) and at the same time we eat dinner (about 6 pm). This past two weeks, she refuses to eat her dog food during the day when we give it to her, but will consistently press her "food" button when its time for bed (about 10pm). She will eat people food that we give her on occasion (the occasional bite of hot dog or peanut butter – i dont like giving her a lot of people food). And when we put tiny bits of shredded cheese in her bowl and mix it with her food, she only eats the cheese and won't eat her food. She's physically fine – playful, happy, not lethargic in the slightest. But only wants to eat when it's bedtime. What can I do to get her to eat on schedule? Is she just being picky?