I've got a video with a series of talking heads, and each has a lower third graphic introducing them. Each graphic is a solid gray matte, slightly transparent, cropped top and bottom and keyframe cropped to slide on and off the screen. Two layers of simple text fade in and out on top of the matte. The speakers are against a white backdrop, and every time the lower third appears the hue (on the backdrop) shifts from off-white to a slight blue. I do not see this in the timeline, only after rendering an H.264 1280x720 .mov. Any ideas what might be going on?