We faced temporary failures due to AWS RDS failover at 18:56 to 18:57 UTC, that occurred in one of our availability zones. Two of our db shards present in that zone were affected, Customers present in those shards were affected during this event. The failover was successful and the errors have stopped.
Failover has occurred due an issue with AWS EC2 API. During the time of event, we received few intermittent request failures and PDF errors.
We will be contacting the affected customers separately via mail.
AWS has acknowledged on the issue, more details on the issue can be found here - https://status.aws.amazon.com/