After https://github.com/solid/node-solid-server/pull/648, node-solid-server will send the `returnToUrl` through a query string rather than using sessions ([here](https://github.com/solid/node-solid-server/pull/648/files#r176765459)'s why). While oidc-auth-manager initially “sees” this query string, it gets lost on the way and is no longer present as `redirect_uri` later on.