Scriptwriting Return / Tab Problems

When I’m in scriptwriting mode and using the return / enter key to go from an action to a character’s name or from a character’s name to dialogue etc… it’ll occasionally work, but most of the time (even though it’s set to go from say, an action to a character’s name), it’ll jump from an action to another action or a character’s name to another character’s name (it clearly says at the bottom of the page what it’s set to do when you hit return or tab, so I know the settings haven’t changed). Also, if I hit enter twice it’ll go to the proper setting, but leave a space between the character’s name and the dialogue, which I then have to go back and delete.

I’ve tried returning to the default settings, but even though I can occasionally correct the problem for a few minutes, it quickly (and seemingly out of nowhere) returns to being buggy.