Actually, I figured out a work around, if not a cure. I spent the better half of an hour looking for this and here is what I found: When you pull the PNG into your time line and it is not transparent, click on the clip and go to the modify option in your menu bar. There, go down to “alpha type” and choose “straight”. I dont know why you have to do it now, but thats what I found works. Hope if helps.