Error: a redirected response was used for a request whose redirect mode is not "follow"

@roshand reported a problem for amp.dev:

https://amp.dev/documentation/components/amp-analytics/?format=websites

```
The FetchEvent for "https://amp.dev/documentation/components/amp-analytics/?format=websites" resulted in a network error response: a redirected response was used for a request whose redirect mode is not "follow".
Promise.then (async)
(anonymous) @ amp-sw.js:1
``