I don’t think that’s true, there was an initial Dynamo outage that was resolved in the wee hours that ultimately cascaded into the ec2 problem that lasted most of the day
Or an NLB could also be load balancing by managing DNS records--it's not really clear what a NLB means in this context
Or there was an overload condition because of the NLB malfunctioning that caused UDP traffic to get dropped
Obviously a lot of reading between the lines is required without a detailed RCA--hopefully they release more info