Specific attributes for principal null were not requested

[Cantor, Scott]

FWIW, you said nothing about how your authentication is even done, but
this old bug for example could be relevant:

https://issues.shibboleth.net/jira/browse/SIDP-490

The authentication engine has had plenty of bugs and issues over the
various releases and any time the bug is in that area, the only thing to
do is upgrade and re-verify the condition.

-- Scott