Modify Node Fields page not saving entered text

I'm having a problem setting an action on a triggered rule to modify a CCK field. I open the Modify Node Fields page, click on the field I want to modify and stick in the token text and save, but when I open it back up, the text is missing. The Field is still selected, and selecting and saving other fields works. But the text entered into the textfield always comes back blank, and when the action is triggered, the field is left blank.

I'm not seeing this behavior on any other module config screen I've worked with today, and I've tried it in two different browsers with the same result.

Thanks.