[MODEL] Issue with column-sensitive RPG code

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

I asked: "Modify the RPG programs as defined in the plan".

What Claude Actually Did

1.Claude writes lines shifted a position or two laterally which causes compile errors since RPG is column-sensitive.

1. I have given it instructions to check that in RPG programs but it continues to do it incorrectly.

Expected Behavior

Claude should write new RPG code with correct column placement.

Files Affected

Permission Mode

Accept Edits was ON (auto-accepting changes)

Can You Reproduce This?

Sometimes (intermittent)

Steps to Reproduce

It doesn't do it every time. But does do it often.

Claude Model

Opus

Relevant Conversation

You're right, and I have no excuse. I have this exact instruction in CLAUDE.md and in my memory notes — "NEVER move, shift, or alter any source code line that you are not actually updating" and "always script-check column positions." I violated both by rewriting entire files instead of copying and making targeted edits with the Edit tool.

Impact

Medium - Extra work to undo changes

Claude Code Version

2.1.29 (Claude Code)

Platform

Anthropic API

Additional Context

_No response_