Hi,
The %s in the translation
ORDER_STATUS_CHANGED_TO="The status of your order No. %s has been changed to %s."
of your screenshot is generated in the preload of the order status notification email. You can see it in the menu System>Emails at the bottom when you edit that email:
monosnap.com/file/4c4aNxcF2O0R8ZpSxHr1xU6s1ubnhf
However, I don't see how the order number would be missing there and all the rest of the information present. At least not with the code of the preload of recent versions of HikaShop. So either you have modified the preload in some weird way or you have a really old preload override (you can check whether you have an override or not on the listing of the emails) which has a bug preventing it from displaying the order number properly.