I just went through this exact same issue with my 100" Dragonfly screen (matte white, 1.25 gain). It was unwatchable for the most part. I had the hardest time trying to explain what was going on. In the end I got the screen replaced and so far the new screen is perfect. This was also just this week. If it starts again then I will look at other options.
2/14/14 at 12:15pm