Technically this should be fixed by changing the logic
in Translatable::get_extra_config(), which modifies the 'defaults'
configuration on the objects it applies to. Since this is called
very early during the configuration bootstrap, it sets whatever
the current value of Translatable::get_default_locale() is there.
Any changes at a later time don't affect newly created objects,
even Translatable::reset() doesn't alter the initially configured 'defaults'.
