It never worked any differently. You are zoomed in 800 % and unlike Illustrator AE does not re-rasterize vector content upon zooming for display purposes. All that matters is how it looks at 100% zoom and Full Resolution. there is nothing wrong. You simply have a misunderstanding here.
It's probably because you rendering at less than full resolution, I had the exact same problem and I realized I'm looking at my project at a quarter quality at 400% zoom, it comes out clean when you fix the rendering quality. By now you would have figured it out im sure, who ever else has this problem this is your answer.