rails admin randomly change language

[buncis]

I have 2 language in my application english and indonesia
and I set my default language to :english
but when I open rails admin sometimes it use indonesia as language and sometimes it use english
(after I close and re-open the rails admin)
how to make it consistent using english?

I have follow this troubleshoot guide btw
https://github.com/sferik/rails_admin/wiki/Troubleshoot#other-issues
adding I18n.default_locale = :en to my rails_admin config

rails_admin (1.1.1)
rails(5.0.0.1)
globalize (5.1.0)
see the models name in sidebar in english it have s(plurals) and the datetime format also changed

[buncis]

it's because rails admin not using rails default controller

config.parent_controller = '::ApplicationController'