Hi Ton
I think you have a lot of translated pages. DNN does not automatically add them even if we select Display module on all pages.
From your persona bar under Content > Pages menu, go to each translated page that you want to make the Restore button appear. Under the Localization tab, look for the line where the "Restore" module is and select the Copy Module checkbox for each language you want. Then click on Update Localization to save.
Thank you!