In two of three segments I shot in one session with an HF R400, there are three vertical white dots and a small white slash in the bottom third of the screen. The two segments were shot in bright sunlight. The third segment, which had no such dots, was shot out of direct sunlight, if that was a factor.
Thanks for posting.
What you are describing could be lens flare. Lens flare is a light scattering effect usually caused by sunlight entering the lens at a high angle, but the source is not just limited to sunlight.
Do you have a sample clip or frame capture we can see?