[BUG] /release-notes changelog cache not refreshing — stuck at 2.1.79 since March 2026

Description

The /release-notes command (and the underlying cache at ~/.claude/cache/changelog.md) has not refreshed since v2.1.79, despite the CLI updating through to v2.1.138. The cache file's mtime is frozen at 2026-03-19.

Steps to Reproduce

1. Run claude --version → confirms 2.1.138
2. Run /release-notes → shows 2.1.79 as latest with no newer versions

Expected Behavior

/release-notes should reflect the current version or at least recent versions. The changelog cache should refresh periodically (e.g. on session start or on update).

Actual Behavior

~/.claude/cache/changelog.md top entry is ## 2.1.79. File has not been written since 2026-03-19, confirmed via stat:

Modify: 2026-03-19 10:48:11 +0800

Environment

• Claude Code version: 2.1.138
• OS: Windows 11 Pro (MINGW64 / Git Bash)
• Shell: bash
• Cache file path: C:\Users\<user>\.claude\cache\changelog.md

Notes

• The cache file exists and is readable — not a permissions or missing-file issue
• ~/.claude/cache/gsd-update-check.json (a separate hook-managed file) updates fine on session start, so the cache directory itself is writable
• No errors are surfaced to the user — /release-notes silently shows stale data
• Related: #5770 (changelog lagging), #48271 (changelog feed quality)