Question Mark Boxes

I have a Touchbar MacBook Pro, that is currently on the Mojave version.

However, recently, several bits of text turn into those little question mark boxes (for the sake of my post I'll call them error emojis). I don't think this is because of Mojave because it hasn't happened before with this version. It also doesn't seem to matter what the text is, but rather where the text is, for example, my touchbar. All text in my touchbar is error emojis. And certain bits of text in the app store, such as my name, suffer from the same ailment.

It's rather annoying, because I can't tell what the text says.

Thanks in advance.