In the VCL UI pack there is a routine that tries to determine which Office version is used. This routine does not work, at least not for Office 2016, when the User does not set a value as most users don't.
In AdvStyleIF the function GetOfficeTheme tries GetOfficeUIThemeValue. That function tests for the setting of key 'UI Theme" in the registry. But this key DOES NOT EXIST when a user does not set a value. In this specific case the default value should be used, which is Colorful (value 0). So when this fails, defferent Office versions are tested and the user ends up with the ugly old ot2003Blue theme, which is still default.
I hope I have layed it out correctly. The only thing that has to be changed is to add a default when an Office version is found, but the UI Theme key is not found.