Statusline permanently disappears after /plan command and other slash commands

Description

Custom statusline permanently disappears during a session and cannot be recovered. This appears to be triggered by slash commands, particularly /plan. Interestingly, even just typing a slash command (before executing) can trigger the disappearance.

Steps to Reproduce

1. Configure a custom statusline in ~/.claude/settings.json
2. Start a new Claude Code session - statusline displays correctly
3. Type /plan (or execute /plan)
4. Observe: statusline disappears and does not return for the remainder of the session

Expected Behavior

Statusline should persist throughout the session, regardless of slash command usage.

Actual Behavior

• Statusline completely disappears
• Cannot be restored without starting a new session
• Sometimes triggered just by typing / followed by command name (before pressing Enter)

Environment

• OS: Windows 11
• Terminal: Windows Terminal / VS Code integrated terminal
• Claude Code Version: 2.x (latest)
• Statusline Config: PowerShell script via settings.json

{
  "statusLine": "powershell -ExecutionPolicy Bypass -File C:\Users\...\statusline.ps1"
}

Additional Observations

• The statusline works perfectly at session start
• Once it disappears, no amount of interaction brings it back
• Other slash commands (like /context) may also trigger this
• Possibly related to UI re-rendering during interactive/modal states

Possibly Related Issues

• #12571 - Statusline doesn't refresh after shell escape commands
• #17020 - statusLine configuration issues in v2.1.1
• #5863 - Statusline disappears with CLI flags