### Answer
It sounds like you're encountering issues with overlapping or garbled responses from the AI, which can be indicative of several potential issues in the configuration or integration of your voice AI setup with Vapi.
1. **Model Configuration Issues**: If multiple models are active or the system prompt within the models isn't correctly isolating its context, it could result in overlapping responses. Ensuring that the configuration aligns with a single task per call might mitigate this issue.
2. **Streaming or Latency Issues**: Even though you've optimized streaming latency, it's possible that network issues or server-side processing delays could be affecting performance. Ensuring that your server is properly scaled and your network is stable might help.
3. **Audio Processing Anomalies**: Issues with the audio input, such as noise or poor quality, could be misinterpreted by the transcriber, leading to erroneous text input to the models and thus confusing outputs. Checking the audio input quality could be a step towards a solution.
4. **Software Bugs or Integration Issues**: There could be a bug in the integration layer between Vapi and the underlying models, or potentially in how responses are handled and delivered back to the end-user. Reviewing logs and system metrics around the times these issues occur could provide insights.
Since this behavior could be due to a complex interaction of components, consider isolating each part of the system (transcription, LLM processing, and text-to-speech) to diagnose where the issue might be more pronounced. This can be done by logging the outputs at each stage to see where the anomalies start.
If the issue persists and is reproducible, contacting Vapi support with detailed logs and system configurations would be advisable to get more targeted assistance.