/plugin shows stale "skills path not found" error after plugin upgrade (references old version cache)

Summary

After Claude Code auto-upgrades a plugin via /plugin → Update now, the /plugin UI keeps showing a skills path not found error pointing to the previous version's cache directory, even though everything else (MCP server, installed_plugins.json, marketplace manifest) is already on the new version. /reload-plugins does not clear the stale reference.

Environment

• Claude Code: 2.1.141
• Node: v24.14.0
• OS: Linux (WSL2) — 6.6.114.1-microsoft-standard-WSL2
• Plugin: context-mode@context-mode (upgrade 1.0.131 → 1.0.133)

Repro

1. Have plugin installed at version X (1.0.131).
2. /plugin → Update now → upgrades to version Y (1.0.133).
3. Run /reload-plugins.
4. Open /plugin and inspect the plugin entry.

Expected

Plugin shows clean status, skills loaded from .../cache/<plugin>/Y/skills.

Actual

context-mode @ context-mode
  Scope: project
  Version: 1.0.133
  Status: Enabled

  Installed components:
  ● Skills: ctx-doctor, ctx-stats, ctx-purge, ctx-insight, ctx-upgrade, context-mode
  ● Hooks: PostToolUse, PreCompact, PreToolUse, UserPromptSubmit, SessionStart

  1 error:
    skills path not found: /home/<user>/.claude/plugins/cache/context-mode/context-mode/1.0.131/skills
    → Check that the path in your manifest or marketplace config is correct

Note the version header says 1.0.133, but the error references the old 1.0.131/skills path. The old cache directory still exists on disk but does not contain a skills/ subfolder (that folder only exists in the new 1.0.133 cache), which is what triggers the error.

Evidence that everything else is already on the new version

• ~/.claude/plugins/installed_plugins.json → installPath: .../1.0.133, version: 1.0.133
• ~/.claude/plugins/marketplaces/context-mode/.claude-plugin/marketplace.json → version: 1.0.133
• ~/.claude/plugins/marketplaces/context-mode/.claude-plugin/plugin.json → version: 1.0.133, skills: \"./skills/\" (relative path)
• claude mcp list → plugin:context-mode:context-mode: node .../1.0.133/start.mjs - ✓ Connected

The only place pointing to 1.0.131 was the stale cache directory itself (which Claude Code never deletes on upgrade) plus whatever in-memory state the running session was holding.

Workaround

1. rm -rf ~/.claude/plugins/cache/<marketplace>/<plugin>/<old-version>
2. Fully exit and restart the Claude Code session (/reload-plugins alone is not enough — the stale path is held in the session's in-memory state, not just on disk).

After that the error disappears.

Suggested fix

On plugin upgrade, Claude Code should either:

• Delete the previous version's cache directory automatically (clean upgrade), or
• Re-resolve ${CLAUDE_PLUGIN_ROOT} and the skills path against installed_plugins.json[*].installPath on /reload-plugins, instead of caching the previous resolution in session memory.

The current behavior leaves users with a confusing persistent error after a successful upgrade and no obvious way to clear it from the UI.