Skip to main content
Applies to:
  • Plan -
  • Deployment -

​
Summary

Invoke calls hung for 400–600s while model generation completed in seconds. The root cause is a Node.js runtime/HTTP2 streaming bug in certain Node versions. Upgrade Node to a version that includes the bug fix (recommended) or apply a temporary client-side workaround.

​
What is happening

The SDK’s invoke path can block for minutes when Node’s HTTP/2/streaming path misbehaves. Model generation and first-token timings remain fast. The long delay happens before or after the model spans — in the SDK invocation/streaming layer — so client-side timeouts (for example 120s) fire even though the gateway and model succeeded. Conditions that trigger it:
  • Running a Node.js runtime that contains a known HTTP/2/streaming bug (see Node.js issue #63989).
  • Using the SDK invoke function or streaming responses over HTTP/2.
  • Long-lived blocking in the invocation/streaming layer on the client process.
You will see this in traces as:
  • Short LLM/generation spans (seconds).
  • Long overall invoke span (minutes).
  • Client-side timeout errors (e.g., timeouts) from your wrapper.

​
Fix or suggestion

Actionable steps:
  1. Check your Node version:
    • node -v
  2. Upgrade to a Node release that includes the fix (use the latest LTS or a release newer than the problematic version):
    • With nvm:
      • nvm install —lts
      • nvm use —lts
    • Or use your distro/package manager to install a supported release.
  3. Restart your application process(s) after upgrading.
  4. Re-run requests that previously hung.
At the time of investigation:
  • Node.js 24.17.0 exhibited the problem.
  • Downgrading to Node.js 24.16.0 resolved the issue for some users.
Because this is an upstream Node.js issue, the complete list of affected versions may change as the Node.js team continues their investigation.

​
How to confirm it worked

  • Reproduce the prior request and verify the overall invoke span is now short (matching the model span). Time-to-first-token should be in seconds, not minutes.
  • Confirm your client logs no longer show the client-side timeout error (e.g., “timed out after 120000ms”) for the same requests.

​
Notes

  • The issue has been linked to a Node.js runtime bug (Node.js issue #63989). If possible, monitor Node.js release notes for the specific fix and choose a patched LTS release.
  • If problems persist after upgrading, collect a minimal repro and the relevant traces showing invoke vs LLM spans and submit them for further analysis.