Ah that explains it.
It appears that during authentication, the username is case insensitive, but when we perform the redirect back to the application (in this case, test login), we are performing a case sensitive lookup of the user’s information to fill in the attribute mapper and that lookup is based on how the user entered their username in the login form (in a case-sensitive fashion).
I’m going to mark this as a bug on our side. We’ll figure out a better way to handle this.
Thanks for sharing the issue.