v0.0.116 ChatVectorDBChain with ChatOpenAI fails with `Should always be something for OpenAI.`
Yes, facing the same issue with `QA with Sources` Chain as well for both `ChatOpenAI` and `AzureChatOpenAI`. ah sorry - will fix
`ChatVectorDBChain` with `ChatOpenAI` fails with `Should always be something for OpenAI.`

It appears `_combine_llm_outputs` added to `ChatOpenAI` in v0.0.116 is receiving a `llm_outputs` list containing a `None` value. I think this is related to streaming responses from the OpenAI API.

see https://github.com/hwchase17/langchain/pull/1785