For about an hour, from 2021-10-12 7:57 UTC to about 2021-10-12 8:55 UTC, MaxCDN, one of the CDN providers that we use to serve traffic, was slow and unresponsive for part of our Japan traffic due to scheduled maintenance in the Tokyo region: https://status.maxcdn.com/incidents/n6s35q0f8gf0.
Customers with significant web traffic volume in Japan were affected. The majority of such customers by traffic are using a version of the LiftIgniter snippet that automatically tries against the Cloudfront CDN when MaxCDN is down, so they were partially insulated. Even so, since there is some time lag for the retry, we did fail to capture data for their end users who bounced before the retry could be triggered, and failed to show recommendations for users who scrolled to recommendation areas before the retry had kicked in.
API integrations were not affected, so app customers in Japan were not affected.