The default behavior when typing a left parenthesis in a dialogue is to automatically insert a parenthetical direction element on a new line.
If you wish to type a left parenthesis within dialogue, press SHIFT+CONTROL+9. In this way you can add "(beat)" within the dialogue element:
However, the item (beat) should be on it's own line rather than being incorporated into the Dialogue. (Screenwriter's Bible, 3rd Edition, p. 137)
Tag: Movie Magic Screenwriter