One possibility is that the keyboard setting is bad for the massive amount of shortcuts we are using. The system default input source is ABC - Extended, which causes ⌥+⇧+f to input a ̰ character. For example, in VS Code, to format a document, one uses ⌥+⇧+f, which inputs ̰ instead of executing the shortcut.
Just change the ABC - Extended input source to ABC.