I did a 3 camera (technically 2) video. The main two were the same Canon camcorder recording in 59.95p in MP4. When playing back a certain portion of one of the camcorders the video in the timeline is normal, but in the preview window it's magnified. If I click on the split screen in the preview window one side is the normal version and the other side is still magnified.
I thought I had remembered it originally being normal size.