GitHub change history: Copilot Code Review is unable to complete reviews

GitHub reported a critical Copilot Code Review degradation starting 2026-09-28 21:16 UTC, resolved at 2026-09-28 22:08 UTC (51 min). Approximately 70% of requested reviews did not complete across all environments; affected users needed to re-request reviews. GitHub attributed the issue to a dependent-service change and reported a revert underway before recovery.