Back when I lived with my parents, we had a dog (Boston terrier) that we fed Purina Dog Chow. We always kept her dish full; if it started getting low, we'd pour some more in. Thing was, she only ate it when someone came home. Literally, when someone came in, she'd dance around, run to her dish, eat some food, come back and dance around some more, run back to her dish and eat a little more, etc. Otherwise, I never saw her touch the stuff.
I think she "got by" on all the scraps we fed her.
Mine won't eat when we aren't home. If I'm gonna be gone for the day, I'll fill the bowl for my own conscience, but they won't eat till we get home.
She probably was hungry before you got home, but wouldn't eat till you did ;~D