This happens all the time with used Xbox Ones - explanation (Off-Topic)

by GrizzNKev, Down the street from Microsoft, Sunday, December 07, 2014, 19:13 (3642 days ago) @ Mid7night

The Home console setting is enabled by default for the first person who signs in to a new Xbox One. Since yours is used, and you've never gone in to change that setting, it is still the home Xbox of the previous owner. With digital download games, they become available on two systems when purchased - the one where the owner is currently signed in, and any account signed in to the owner's Home console. Whoever you bought your Xbox One from bought a black friday bundle and just redeemed the included games. If you never tell them, you'll get every game they buy digitally for free.