I loaded up an old template I had made in v.2 for a client...needed to make some new renders.
I was saving as PNG with an alpha. Then I noticed all the edges were all jagged. I saved the project and installed v.2 again.
I didn't change a thing, but the rough edges were gone and everything was back to being smooth.
Is there a setting in v.3 I have to change to get my smooth alpha edges back?