Hi @user4, welcome and thank you for your question! I have changed your post’s title to bring it in line with the question guidelines and thus make it easier to understand from the title:
Good titles are questions you would ask your friend about Typst.
If you mean that e.g. $"C"$ will still result in “C” instead of “C”, that is actually a bug that has been long fixed. You are likely still using Typst 0.12 instead of 0.13. In the web app, you can click on the gear icon 
(bottom left) to find that setting.
That said, I think upright(C) is the preferred way of writing this anyway.