It’s hard to tell without looking over your shoulder but the Canvas only shows a limited number of processed pixels. It’s likely just an artifact of your machine’s real time capabilities and the size of the Canvas window. If the coordinates of the clips do not actually shift and the render is okay, I’d have to say you have nothing to worry about. Try changing your effects handling and rendering from whatever you’ve got to Faster (linear).
Similar questions have been popping up ever since v5 shipped.
Since you’re posting this same question in multiple forums, please go back and update them all once you’ve solved this issue.
bogiesan
This is my standard sigfile so do not take it personally: “For crying out loud, read the freakin’ manual.”