Subscription returns both a delete _and_ an update when an update is made

I've got a Quickslice instance setup (quickslice.gamesgamesgamesgames.games). All of the basic operations are working smoothly, but I'm seeing strange behavior with real-time subscriptions. When I update a record, the subscription sends both a delete and and update event.

I'm happy to share more details if necessary, but I wanted to start by just making sure I'm not missing something. Is this the way it's supposed to work?

This is the mutation I'm sending to make the update:

mutation PutGame ($name: String!) {
  createGamesGamesgamesgamesgamesGame (
    input: { name: $name }
  ) {
    uri
  }
}