Basic Auth decode User wrong

I've a Application which uses Basic Auth. For that I've created a SSO Basic Profile. The variables that are used where filled in the APM Profile:

 

session.domain_user >> expr { "[mcget session.logon.last.logonname]" } session.domain_pass >> expr { "[mcget -secure session.logon.last.password]" }

 

When trying to access the Applikation it schows me 401. After a tcpdump I saw that the password was right but the user shows trash:

 

Basic JENLJHY0M3hGdTE1JHdRajJnZXVYOGVjbExiZzdQV3lSTTF3NUloY2ZTYjNLS1J3MTFsaGFqZkk9OlN0YXJ0MTIz

 

This Basic Auth String I saw in the Dump. Decoded it looks as shown below.

 

$CK$v43xFu15$wQj2geuX8eclLbg7PWyRM1w5IhcfSb3KKRw11lhajfI=:Start123

 

So the Password is right but the User is wrong.

 

Any ideas ?