Washington's health plan finder allows you to set a billing date to automatically deduct your premium. The Bruner family set that for late December but got billed two weeks early instead.
It is possible that the insurance company is at fault here. They are the ones ultimately receiving the money from the Bruner's account. But as the manager of the marketplace, Washington state is at least partly at fault. A spokesperson for the site told King 5 they are looking into the problem.