Here's the update from the horse's mouth:
[5:19 AM PDT] We are investigating reports of problems resolving some DNS records hosted on Route53 using the third party DNS resolvers 8.8.8.8 and 8.8.4.4 . DNS resolution using other third-party DNS resolvers or DNS resolution from within EC2 instances using the default EC2 resolvers are not affected at this time.
[5:49 AM PDT] We have identified the cause for an elevation in DNS resolution errors using third party DNS resolvers 8.8.8.8 / 8.8.4.4 and are working towards resolution. DNS resolution using other third-party DNS resolvers or DNS resolution from within EC2 instances using the default EC2 resolvers continues to work normally.
[6:10 AM PDT] Between 4:05 AM PDT and 5:56 AM PDT, some customers may have experienced elevated errors resolving DNS records hosted on Route 53 using DNS resolvers 8.8.8.8 / 8.8.4.4. This issue was caused by a problem with a third-party Internet provider. The issue has been resolved and the service is operating normally.