gemini model: UnexpectedModelBehavior: Expected exactly one candidate in Gemini response

### Question

I frequently encounter the mentioned error and have no idea what to do. Unfortunately, nothing is clear. What should I do? I understand what the issue is. I'm trying to retry my request, but in many cases, my problem doesn't get solved.

### Additional Context

 If it's helpful, my use case is converting relatively long audio files to text.
model: google-gla:gemini-2.5-flash