e.g you open a new Chrome, go to incognito mode, and load:

https://timbl.com/timbl/2017/Solid/HighLevelIssues/index.ttl#this

You end up getting to

https://timbl.com/timbl/2017/Solid/HighLevelIssues/index.ttl

This is only a problem the first time, because of all the redirects, not later when the login state has been stored.
Seems to be a problem with eith TLS or OIDC forms of login. I thought @RubenVerborgh fixed this, at least for OIDC.