This incident is now being marked as resolved.
Thanks for your patience.
Between approximately 08:30 and 09:10 this morning users may have experienced slow or failed request to some application services. The release of a critical platform update caused a restart of all services during that time. During this period one of the nodes hosting some app services became unhealthy and traffic that was balanced to that node began to fail.
This issue has been resolved and we are continuing to monitor.