Can't Show Korean In this version.
I Think this is unicode error

You need to provide more information. "Can't show Korean" is not enough.

If translations are missing, please provide information on which. If you are seeing errors, please provide those errors
You didn't even use the issue template. This is not enough to help you with.

I set it up in Korean. Only some items in Immersive Engineering mod are displayed in Korean and others in English.

I'm sorry. I'm so clumsy.

Yeah because the translation is incomplete. We rely on people submitting translations. I don't know Korean, I can't write it.

You are free to contribute an updated translation in the form of a pullrequest, we'd be happy to merge it.

"item.immersiveengineering.shield":"\uc911\ud615 \ubc29\ud328"

This is part of the Korean translation file. As you can see, there is something that seems to be an error in Unicode. I have already modified it arbitrarily, but it is still show up English.

Where are you seeing these issues ingame? That's what I am asking for.

If you set your game to Korean, what problems do you see? Please provide screenshots and more helpful explanations. Because you are not delivering any worthwhile info right now.