Environment with metadata default language set to German or any other non-English US.


Locale resolution is done when user runtime has been created, at that time, the metadata locale defaults to interface locale (in this example > German) not being directly specified.
However, when importing users via Web SSO the call LoginSimpleSecurityPlugIn happens before the user runtime is created and hence metadata locale will default to the Intelligence Server's in-line user runtime, which is English US.
It has been confirmed that this issue is addressed with 2021 U10. Please upgrade to 2021 U10 or higher to take advantage of the fix.