So I've had this issue with a few shots in this project. I've never seen AE do this before. Basically I am doing my roto on an adjustment layer then taking my footage underneath it and setting the Track Matte to Alpha (the way I've always roto'd) and for some reason it is shrinking my footage down to fit within the roto. It's only doing this for some frames - not all frames - and when I purge it will sometimes go away.
Is this an issue with my graphics card? I just updated CC to the latest version and it seems to be even worse.