I'm using Magix Movie Edit Pro 2014 and there's this rainbow background that seems to appear and the preview will flicker to every once in a while when I edit. However, this background has made editing a bit annoying but hasn't caused an issue until now. On my last project, the rainbow background will flicker in and out while and appear on my export.

What is causing this? And how can I stop it from doing so? Thank you.