I experienced this many times, but I forgot to ask every time.
Here’s the scene.
I set my language to Traditional Chinese (using a mod of course), and I also enable a mod that is not localized.

When I first select the vault, it is localized.

Then I select the other item. It’s not localized of course.

But then, I select the vault again. It’s unlocalized! 
And many other strings fall back to English too.

Can this be fixed? 