Buildkite change history: Delayed notifications

Buildkite reported a major incident delaying build and job notifications for a subset of customers, affecting email, GitHub commit status, Slack and webhooks. It started at 2026-05-28 20:20 UTC and was resolved at 2026-05-28 21:18 UTC; the computed duration was 57 min. Delayed notifications also delayed downstream CI, merge or deployment workflows for some customers.