Effective File Search 6.8.1 can not longer switch to german localization when ros has been installed with a specific unattend.inf

ros 0.4.8-RC-15-g0b82612 gcc dbg & 0.4.9-dev-36-g07f3691 are affected.
Effective File Search 6.8.1 from rapps.

When trying to switch language to german via menubar/language/german
it erroneously does not change the language. Instead it displays a messagebox
german.png

and throws a delphi exception

(../dll/win32/kernel32/client/except.c:725) Delphi Exception at address: 004A2661

(../dll/win32/kernel32/client/except.c:726) Exception-Object: 00855700

(../dll/win32/kernel32/client/except.c:727) Exception text: 846950

even after enabling break on first chance it does not break into debugger to allow me collecting a stacklog

Switching to other languages e.g. french does work properly.

In 0.4.7rls.png we could still properly switch to german (no delphi exception) edit:but only without that unattend.inf file.

I double checked on 0.4.9-dev-50-g182a310: The issue can only be made happen when we install ros via the attached unattend.inf. Without the attached unattend.inf the issue will not happen!

This is no regression that has been recently introduced by a commit of us.

The trigger is the unattend.inf.
I double-checked also: it is not dependant on whether gecko is part of the installation or not.
I guess the language-specific settings in the unattend.inf play a role here.