Real-time transcription suddenly stops/drops out after 1.5-2 minutes (~20-25 words), WebSocket closes unexpectedly (e.g., code 3005), no further transcripts despite ongoing audio input. May show partial/final transcripts then silence. Error in on_close/on_error like "Input duration violation" or no error but session ends.

WebSocket session closure due to protocol violations: audio chunks outside 50-1000ms, sending faster than real-time, invalid messages/JSON, or session limits. In SDK (e.g., Python RealtimeTranscriber), may appear as abrupt stop after ~1.5-2min speech due to unhandled closure or stream issues. Observed in [GitHub issue #107](https://github.com/AssemblyAI/assemblyai-python-sdk/issues/107) (Jan 24, 2025).