$vectorSearch is not allowed

MongoDB Atlas Vector Search
,
22

I am trying to query multiple Vector Embeddings with $unionWith

Code:

const documents = await collection
          .aggregate([
            {
              $unionWith: {
                coll: "SearchLeads",
                pipeline: [
                  {
                    $vectorSearch: {
                      queryVector: embedding,
                      path: "industry_embedding",
                      numCandidates: 10000,
                      limit: 30,
                      index: "default",
                    },
                  },
                  {
                    $vectorSearch: {
                      queryVector: embedding,
                      path: "city_embedding",
                      numCandidates: 10000,
                      limit: 30,
                      index: "default",
                    },
                  },
                ],
              },
            },
          ])
          .toArray();

        return documents;

and I am getting this error while searching $vectorSearch is not allowed within a $unionWith’s sub-pipeline reference.

Cluster version: 6.0.13
Tier: M10 (General)