[BUG] Getting "No task found with ID" from subagent

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?

I keep getting this - "No task found with ID" when subagent finished work. Unlike in other issues, this is only ever happens when I have one subagent, no parallel ones.

What Should Happen?

This error should not be shown and main agent should correctly receive output from subagent.

Error Messages/Logs

● Task Output ac3db3a
  ⎿  Error: No task found with ID: ac3db3a

Steps to Reproduce

1. Ask agent to use subagent (in a sequence, not parallel)
2. Eventually you will get this error

This is random and maybe happens in one in 10 runs? This does waste a lot of tokens, because once this starts happening, all context used by subagent is lost and this wastes my quota.

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.0.74 (Claude Code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

VS Code integrated terminal

Additional Information

_No response_