[BUG] Voice session reply delivery lag — responses consistently arrive one turn behind

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Across multiple voice sessions (first observed 2026-10-03, recurred 2026-10-05, different sessions, not a single stuck connection), assistant replies fail to reach the user in sync with the conversation.
Symptoms:

1. A background-task completion gets acknowledged correctly on the assistant's side (reply generated immediately, no delay, no tool calls first) — but the user reports never hearing it, only getting a response after manually asking "did it land yet?"
2. On a plain synchronous exchange, the user answers a direct question, the assistant replies in the very next turn — but the user reports the reply didn't arrive, and that the assistant's next response answers an earlier question instead of the current one ("you're one question behind every time you answer me").
3. User-sent content (e.g., a pasted screenshot) occasionally never arrives on the assistant's side at all, with no trace in the transcript.
4. User has sent the same content twice, apparently believing the first send failed, when the assistant's transcript shows it was received and processed normally both times.

What's been ruled out:
Not a reasoning or response-ordering mistake on the assistant's side — in at least one documented instance, the correct reply was generated immediately and correctly, yet the user did not receive it. No tool-call delay or silent chain-of-calls was responsible.

Suspected cause:
A transport/delivery issue in the voice pipeline between generated assistant output and what the user actually hears, and/or between user speech and what reaches the assistant — not visible or diagnosable from inside the session (no logs/tools available at that level show where the drop occurs).

Workaround attempted:
Restarting the session. This cleared the symptom temporarily on 2026-10-03 but it recurred in an unrelated fresh session on 2026-10-05, indicating it's a persistent bug, not a one-off stuck connection.

Request:
Investigation into voice-session message delivery reliability — specifically turn-ordering/sync between generated responses and audio delivery to the client.

What Should Happen?

Claude should answer the current user question and not be lagging one question behind.

Error Messages/Logs

Steps to Reproduce

Not sure how to reproduce. It happens after a while during a session but once it happens it is constantly one question behind. Only fix so far is to restart the session.

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

October 3rd, 2026

Claude Code Version

2.1.283 (Claude Code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

_No response_