Not getting cited files as a part of the API response

[anandinobec]

I have been using file search feature for the last 5 months. For the last 1 week the response that i get back from the API is very inconsistent. In my vector store i stored the files and use to query them for answers. sometime back, it use to respond back with the file name as a part of the response which is helpful in mapping back the response to the particular document from which the summary of the response is generated. But, off late the file name is not coming as a part of the API response. I even tried changing the system instruction to force the API to add the file as a part of the response. That didn’t help too. Right now the file_citations array is coming back as empty. I had a properly working prototype a week ago. But now, this is causing major issues. Do we have any systematic way to resolve this issue? any changes to the system instruction or anything else that i can do?