[BUG] Claude sometimes claims a bug is fixed even when code changes and environment evidence are inconsistent.

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 asked Claude Code to debug and fix a failing issue.

The run produced mixed evidence (some signals looked better, others did not), but Claude still said the issue was fixed after changing both source files and the environment state.

In short: it reported a confident fix even though the evidence was contradictory.

What Should Happen?

Claude should preserve uncertainty when the evidence is inconsistent. It should not present a definite repair claim unless the fix is actually established by the observed results.

Error Messages/Logs

Validation signals were inconsistent across steps (mixed pass/fail evidence).
Observed bad behavior: Claude still reported a definitive fix despite contradictory evidence.

Steps to Reproduce

1. Set up a bug scenario where repeated checks produce mixed signals (some pass, some fail, or results change between runs).
2. Ask Claude to diagnose and fix the issue end-to-end.
3. Ask for a final yes/no fix conclusion.
4. Compare Claude's conclusion with the actual evidence from commands/tests and file changes.
5. Reproduction matches if Claude reports a definite fix despite contradictory or incomplete validation evidence.

Claude Model

Other

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.76

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

WSL (Windows Subsystem for Linux)

Additional Information

_No response_