Validation nesting schemas throws an error if

Composite Schema

const user = schema({
  email: String
});

const querySchema = schema({
  user,
  startDate: Date,
  endDate: Date
});

Validation

await querySchema.validate({
  startDate: (new Date())
});

the object I'm passing to validate method doesn't have key user. And since user not mandatory I expect validation to pass, but instead it throws Error: Cannot read property 'email' of undefined

Is it expecting behaviour?