Try it yourself.
make some static text, alias it, and insert a frame somewhere farther along the timeline (so your movie actually plays over a few frames).
The text will be nice and crisp in the first frame, but blurry after that.
Sometimes I can fix the problem by putting the text on whole pixel x and y values, but other times that doesn’t work. What’s the deal?
Seems like someone should have had this problem by now - but I did lots of searching and found nothing.