[MODEL] Opus 4.6 Thinking : Lying behavior.

Preflight Checklist

• [x] I have searched existing issues for similar behavior reports
• [x] This report does NOT contain sensitive information (API keys, passwords, etc.)

Type of Behavior Issue

Claude ignored my instructions or configuration

What You Asked Claude to Do

Told claude to find all the project that cause the same error.

What Claude Actually Did

Issues

1. False claim "it's clean" — User asked me to check all files for the double-count

formula. I searched but missed dashboard.py. Told the user no other files had the issue.
This was wrong and wasted significant time.

1. Repeated failed fixes on the same bug — Attempted 4 different approaches to fix the

credit double-count:

• Attempt 1: Filter by debt_treatment_ids in reports.py → wrong treatment_id, didn't

work

• Attempt 2: Subtraction approach in reports.py → worked
• Attempt 3: Filter by debt_tids in dashboard.py → same wrong treatment_id, didn't work
• Attempt 4: Subtraction in dashboard.py → broke the dashboard (no data shown)
• Attempt 5: Revert + redo subtraction

1. Extremely slow response time — Simple sum fix took multiple rounds over 30+ minutes.

User repeatedly complained about speed.

1. False SSL cert expiry alarm — Told user cert expires "tomorrow" which was wrong. Cert

was valid until June 2026. Caused unnecessary panic.

1. Did not learn from first mistake — The treatment_id filter approach failed in

reports.py, yet I tried the exact same approach in dashboard.py.

1. Overconfidence — Presented findings as definitive ("only in daily report") without

thorough verification.

What should have happened

• Search ALL files with grep -rn before claiming "clean"
• Apply the same working fix (subtraction) to dashboard.py immediately
• Test locally before deploying
• Be faster and more direct

• Search ALL files with grep -rn before claiming "clean"
• Apply the same working fix (subtraction) to dashboard.py immediately
• Test locally before deploying
• Be faster and more direct

Files Affected

python script

Permission Mode

Accept Edits was ON (auto-accepting changes)

Can You Reproduce This?

Haven't tried to reproduce

Steps to Reproduce

_No response_

Claude Model

Opus

Relevant Conversation

Impact

High - Significant unwanted changes

Claude Code Version

2.1.91 cli

Platform

Other

Additional Context

_No response_