Apollo + MSW issue with Boolean

[mlaw93]

I have a query that fails with apollo when using msw. With most of my queries I add the __typename and it resolves this issue, but for some reason the response from msw doesn't work with this type of query that has no __typename

Request:

query {
  emailExists(email:"[email protected]") {
    is
  }
}

Response:

{
  "data": {
    "emailExists": {
      "is": true
    }
  }
}

Any ideas on how to resolve?