Claude Code makes edits during plan mode before user approves the plan

Description

When plan mode is active, Claude Code is supposed to be read-only (except the plan file). However, Claude proceeded to edit .github/workflows/main-validation.yml using the Edit tool while plan mode was still active — before the user approved the plan and before ExitPlanMode was called.

Steps to Reproduce

1. Enter plan mode and create a plan for Task A
2. User approves the plan, ExitPlanMode is called, Task A is implemented
3. Enter plan mode again for a new Task B
4. Claude begins editing files for Task B before the user approves the new plan and before ExitPlanMode is called

Expected Behavior

Claude should remain read-only (except the plan file) until the user approves the plan and ExitPlanMode is called.

Actual Behavior

Claude carried over the "approved" mental state from the prior plan (Task A) and began implementing the new (unapproved) plan (Task B) immediately, making file edits while plan mode was still active.

Environment

• Claude Code CLI
• Model: Claude Opus 4.6 (1M context)
• macOS Darwin 25.3.0