SearchResponseRequestParams doesn't match with actual API response

When performing a multiSearch (union) on two collections, I get the following response:

{
  "found": 131,
  "hits": [ ],
  "etc": { },
  "union_request_params": [
    { 
      "collection": "collection_one",
      "first_q": "test",
      "found": 30
      "per_page": 18
      "q": "test"
    },
    { 
      "collection": "collection_two",
      "first_q": "test",
      "found": 101
      "per_page": 18
      "q": "test"
    }
  ]
}

However, when looking at the SearchResponseRequestParams-type, it expects the following:

export interface SearchResponseRequestParams {
    collection_name?: string;
    q?: string;
    page?: number;
    per_page?: number;
    first_q?: string;
    voice_query?: {
        transcribed_query?: string;
    };
}

The collection_name does not match with the actual collection-property, thus my typing is now broken.

More context

Request:

const searchRequests: MultiSearchRequestsWithUnionSchema<
  Array<CollectionOneResult | CollectionTwoResult>,
  string
> = {
  union: true,
  searches: [
    {
      collection: `CollectionOne`,
      q: "test",
      query_by: "title,content,intro",
      filter_by: "_level:0",
    },
    {
      collection: `CollectionTwo`,
      q: "test",
      query_by: "title,review,description",
      filter_by: "_level:0",
    },
  ],
};

const commonParams = {
  limit: 18,
  page: 1,
};

// Perform the actual query

const results = await client.multiSearch.perform<
  Array<CollectionOneResult | CollectionTwoResult>,
  string
>(searchRequests, commonParams);

// This line breaks
const collections = results?.union_request_params?.map((req) => req.collection); // Expects collection_name

Start at the SearchResponseRequestParams type and the result returned by multiSearch.perform, then compare union_request_params with the API response shown in the issue. Done means the response type represents the returned collection property and the example access to req.collection type-checks.