## What Happened

When an embedding request is partly served from the cache and partly forwarded to the upstream provider, the merged response returned to the client contains duplicate and wrong `index` values in `data[*]`. The duplicates cause downstream clients (e.g. our Java ETL using Apache HttpClient) to reject the response as malformed.

The cache write path keeps the indices correct, and the DB spend log re-enumerates them — so this bug is invisible in `LiteLLM_SpendLogs.response`, only the client-visible response is broken.

## Affected Versions

Reproduced on **v1.86.2** and confirmed still present on `main` (HEAD `f27df8d` at time of writing).

## Root Cause

`litellm/caching/caching_handler.py`, function `_combine_cached_embedding_response_with_api_result` (lines 590–640).

Cache hits are inserted with the **final position** as `index` (correct, see `_process_async_embedding_cached_response` at lines 444–448):

```python final_embedding_cached_response.data[idx] = Embedding( embedding=embedding_data, index=idx, # position-based — correct object="embedding", ) ```

But when merging the provider's response, items are taken verbatim with their **sub-…