Similar to the last incident, a database cluster node started misbehaving and, although it would accept connections, no queries would run as if the user didn’t have permission to do so. This caused the application to become inaccessible for some clients, although others could just not have noticed the issue as their requests might have been allocated to a different database node.
The investigation is still in progress, aws is working on this case.
While we are working hard to deliver the best experience to our customers, we apologize for any inconvenience that this might have caused.