Alpha tween not working

1

I’ve animated one text line to come in from left to right and another text line to come in from right to left. They are both supposed to fade in at the same time as they move. For some reason when I publish->preview the animation, the fade in doesn’t work, the text just remains opaque. However, if I preview the animation by choosing it in the library and hitting the play button it works fine. Any idea how I correct this so it works properly when I publish->preview it.