Buildkite change history: Issues with webhook ingestion, GraphQL queries

Buildkite reported a major incident affecting webhook ingestion, GraphQL queries and some web requests, starting at 2026-09-22 20:07 UTC and resolved at 2026-09-22 20:50 UTC (42 min). The postmortem places customer impact between 19:09 and 19:32 UTC: 2.0% of webhook ingestion requests and 20.3% of external GraphQL requests returned HTTP 500 errors.