Finally some info, but seems like they downplayed it a bit :
7:28 AM PDT Between 6:47 AM and 7:10 AM PDT we experienced increased launch failures for EC2 Instances, degraded EBS volume performance and connectivity issues for some instances in a single Availability Zone in the US-EAST-1 Region. The issue has been resolved and the service is operating normally.
At Zapier we saw half the internet blip for a bit (us too), but it seems to have been short lived. Approximately Jul 27, 2017 13:47:45 to Jul 27, 2017 13:59:33 (UTC).
There was a network outage in one of the useast1 AZs at 1:53pm utc for about 10 minutes. I had a db instance that was totally unreachable during that time.