Today, on March 15 2019 from 16:34:15 UTC to 16:35:12 UTC there were some orchestration failures in the US region due to an internal system upgrade.
There were not many failures (around 20, so very few are affected), but if you had an orchestration running at that time, please check to make sure that you were unaffected.
We are working on making sure that this will not happen again for any future upgrades.