Something similar happened at the CDN I work for about 10 years ago… a custom configuration we made for a customer had a typo in it (it was on the host matching

Something similar happened at the CDN I work for about 10 years ago… a custom configuration we made for a customer had a typo in it (it was on the host matching regex… the regex had a trailing |, which caused it to match every host)… this caused every request for any customer to be sent to that one customer. It quickly overwhelmed their origin and caused an outage (the largest one we have ever had, before or since). We wrote a system that is still in place today that loads all new configurations and sends test traffic to it, to make sure the results are as we expect.