Increased error rate in AWS US stack

We're investigating increased error rate in AWS US stack ( Next update in 15 minutes or when new information is available. 

UPDATE 04:40 UTC: We have identified and replaced a number of corrupted nodes with healthy ones, and operations are now back to normal. We apologize for the inconvenience caused.

UPDATE 05:40 UTC: This issue appears to be ongoing, and a new symptom has been identified: jobs are taking longer to start than usual, or are getting stuck in a waiting state. The next update will be in 30 minutes.

UPDATE 06:25 UTC: We're still investigating the issue. Next update in 30 minutes.

UPDATE 07:15 UTC: We have found the root cause and we're fixing it. 

UPDATE 08:44 UTC: The root cause was fixed and all operations are back to normal.