So, I have simple graphic made in After Effects that I need to drop over the top of a timeline in FCP.
I exported the graphic from AE as RGB+Alpha and Straight (Unmatted) which usually works fine.
In this case, when I drop in the graphic over my timeline, it shows up over the existing video fine except for the fact that it creates these little pixelated artifacts around the edges of the graphic.
Not sure what causes this and what can be done to solve it.
It turns out that the issue was the codec that I was editing in.
I was unknowingly editing in the terrible H.264 codec using video shot on a 5D.
I switched my timeline to ProRes 422 and it cleared the issue right up.