Invalid json syntax, expected json object but was json primitive

Question

When creating an index in Google Vector Search platform the index creation failed with this error:

 embeddingId: EMBEDDING_ID_NOT_APPLICABLE
        errorMessage: Expected a com.google.gson.JsonObject but was com.google.gson.JsonPrimitive;
          at path $
        errorType: INVALID_JSON_SYNTAX
        rawRecord: '    -0.0223593935, 0.0273346137, -0.0281442013, -0.00227753539,
          0.0143363187,'

This is how my .json file looks like:

{
  "id": "1",
  "embedding": [
    -0.0320996083, 0.0598638132, -0.000723437872, 0.0202979278, -0.00374370185,
    0.020754844, -0.028198, -0.00302006351, -0.00580240414, 0.0216173287,
    0.0225891396, 0.00469718548, 0.0182211958, 0.0842230618, -0.0173235275,
    ........................(has about 286 more lines)...................
    0.00816405565, 0.0117803486, -0.0233089756, -0.00427557155, -0.00267161848,
    -0.00266683474, 0.00760478387, 0.0102972658, -0.00593171781, 0.00593384868,
    0.0122984545
  ]
}

this is my metadata:

{
  "contentsDeltaUri": "gs://match-it-fast-us-central1/gdelt_gsg/index-1",
  "config": {
    "dimensions": 512,
    "approximateNeighborsCount": 150,
    "distanceMeasureType": "COSINE_DISTANCE",
    "algorithm_config": {
      "treeAhConfig": {
        "leafNodeEmbeddingCount": 1000,
        "leafNodesToSearchPercent": 5
      }
    }
  }
}

i successfully uploaded the json file into my google cloud bucket using this code block:

gsutil cp ./embeddings/testembedding.json gs://match-it-fast-us-central1/gdelt_gsg/index-1/ 

and created index with this block of code successfully:

gcloud --project=myproject ai indexes create --display-name=demo-image-index --description="Image Demo" --metadata-file=metadata/gdelt_gsg_index_metadata.json --region=us-central1

The index can be seen on vector search index list and the status shows creating and returns with a failed response: here is the error image of failed creation