[BUG] Account marketplace "Sync automatically" never re-syncs on push; only manual "Check for updates" moves the synced commit

Environment

• claude.ai (web) and Claude Desktop (macOS, Darwin 25.4.0), same account
• Marketplace: private GitHub repo haydenmoorecpa/hfm-skills, added as an account marketplace (Settings → Plugins → Add → Add marketplace), .claude-plugin/marketplace.json at repo root, one plugin with 13 skills
• Claude GitHub App installed on the account with All repositories access, authorized, used within the week; no repo-level webhooks
• Plugin version is generated from a content hash and bumped on every content change, so each push is distinguishable on the plugin page

Summary

The marketplace's ⋮ menu shows Sync automatically — "Re-syncs on GitHub changes", on by default. It never fires. Across ~9 hours and 8 pushes to the default branch, "Synced commit" on the marketplace card and the plugin version never moved. ⋮ → Check for updates pulls the new commit within ~20 seconds every time, so the pipeline itself works; only the automatic trigger does not.

Timeline (2026-09-11, US Eastern, read from the Manage marketplaces dialog on claude.ai)

| Time | Event | Synced commit shown | Plugin version shown |
|---|---|---|---|
| ~10:30 | Marketplace added | c13c5b5 | 1.2.0 |
| 12:18 | Push, version → 1.2.1 | | |
| 12:32 – 12:45 | Read 3× | c13c5b5 | 1.2.0 |
| 12:46 | Check for updates clicked | bfb9031 (toast "Updated to bfb9031") | 1.2.2 |
| 12:46 – 21:40 | 7 more pushes (versions up to 1.2.6) | | |
| 18:00, 20:52 | Read | bfb9031 | 1.2.2 |
| 20:52 | Sync automatically toggled off → on | | |
| 20:54, 20:58, 21:07, 21:40 | 4 pushes after the toggle | | |
| 21:02, 21:14, 21:24, 21:54 | Read | bfb9031 | 1.2.2 |

Expected

A push to the repo's default branch re-syncs the marketplace (or at least the plugin page reflects the new version within some bounded interval) while "Sync automatically" is on.

Actual

Nothing re-syncs until a human clicks Check for updates. Toggling the setting off and on does not change this.

Desktop log observations (~/Library/Logs/Claude/main.log)

• [PluginsFetcher] … 2 plugins from 2 marketplace(s) runs roughly hourly — it lists the account's plugin snapshot, it does not re-sync the repo.
• No line resembling an automatic marketplace sync appears at any time on 2026-09-11 or 2026-09-12.
• The only refresh lines are the manual ones (Refreshing marketplace: hfm-skills / Marketplace refreshed), and those were for the local Claude Code clone (a separate registration of the same repo), not the account marketplace.

Notes

• Possibly related: #86818 (Check for updates on an account-scoped git marketplace fails on first attempt — not observed here; ours succeeds first try but never runs unprompted) and #17361 (local plugin cache never refreshes).
• Happy to provide account/marketplace identifiers privately.