Using query variables does not generate the same errors as statically filled queries

[NT-Timm]

Hello,

We've run into an issue with how error are not handled correctly when using Query Variables to fill a Query/Mutation.

Here is an example how it goes wrong: Mutation:

mutation createUpdateTest($input: [CreateUpdateTestInput!]!) {
  createUpdateTest(input: $input) {
    items {
      id
    }
  }
}

Query Variables:

{
  "input": {
    "testa": "test",
  }
}

Output:

{
  "data": null,
  "errors": [
    {
      "path": null,
      "locations": null,
      "message": "The variables input contains a field that is not defined for input object type 'CreateUpdateTestInput' "
    }
  ]
}

Note the lack of the missing field in the error

And here is an example how it goes correctly: Mutation:

mutation createUpdateTest {
  createUpdateTest(input: {testa: "test"}) {
    items {
      id
    }
  }
}

Output:

{
  "data": null,
  "errors": [
    {
      "path": null,
      "locations": [
        {
          "line": 2,
          "column": 21,
          "sourceName": null
        }
      ],
      "message": "Validation error of type WrongType: argument 'input' with value 'ObjectValue{objectFields=[ObjectField{name='testa', value=StringValue{value='test'}}]}' is missing required fields '[test]' @ 'createUpdateTest'"
    }
  ]
}

Note the actual showing of the missing required fields.

Have we made a mistake with our appsync configuration? Is this working as intended or is this a bug?