[Bug] Claude Code intermittent 500 Internal Server Error during longer-running repo work

Bug Description
Claude Code intermittently fails with API 500 internal server errors during longer-running repo work.

Claude Web works normally with the same account, and Claude Code also works for trivial prompts after /login, but longer-running repo work still intermittently fails with API 500 errors.

Account: ro@threshhold.com
Claude Code version: v2.1.77
Machine: MacBook Pro
macOS: 26.2 (Build 25C56)
VS Code: 1.111.0 (ce099c1ed25d9eb3076c11e4a280f3eb52b4fbeb, arm64)

Observed behavior:

1. Initial repeated 500 errors in Claude Code across multiple repos
2. Removed and re-invited user to Anthropic org/workspace
3. After re-invite, Claude Code returned 401 authentication_error invalid credentials
4. Ran /login and authentication succeeded
5. Trivial prompts then worked
6. Later, longer-running repo work failed again with API 500 after about 2m 41s
7. Claude Web works normally with the same account
8. I ran /doctor and found duplicate Claude installations
9. I removed the leftover npm global install and now only the native Claude binary remains at /Users/rocean/.local/bin/claude
10. I reran /doctor and the duplicate-install warning is now gone

Request IDs:
req_011CZ9E5K8sLWmZU77BC43Zw
req_011CZ9EXfg7UWc6em1nwZ6C4
req_011CZ9EhrXFoLNUBi7u0Mp8p
req_011CZ9FTKRA2hab8YnHC0diW

This appears to be Claude Code-specific or longer-running-operation-specific, not a full account auth failure.

Environment Info

• Platform: darwin
• Terminal: vscode
• Version: 2.1.77
• Feedback ID: 5c94003f-5ebb-4251-b1d6-1f5db2c56a42

Errors

[{"error":"Error: NON-FATAL: Lock acquisition failed for /Users/rocean/.local/share/claude/versions/2.1.77 (expected in multi-process scenarios)\n    at ovT (/$bunfs/root/src/entrypoints/cli.js:2648:2192)\n    at uxq (/$bunfs/root/src/entrypoints/cli.js:2648:1336)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-03-17T20:06:05.101Z"},{"error":"Error: 500 {\"type\":\"error\",\"error\":{\"type\":\"api_error\",\"message\":\"Internal server error\"},\"request_id\":\"req_011CZ9FtKRA2nab8yNhCDdiW\"}\n    at generate (/$bunfs/root/src/entrypoints/cli.js:409:9268)\n    at makeRequest (/$bunfs/root/src/entrypoints/cli.js:448:5435)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-03-17T20:08:53.084Z"}]

Please investigate whether this is a Claude Code-specific runtime/backend issue or a Claude Code session/account-state issue that only appears during longer-running operations.