I've run into this problem a couple of times when shooting. The first was when shooting a snowcat - the white lights showed up purple. I have no idea what causes it, but it seems to happen only when shooting directly into industrial lighting. Attached is a screenshot (not from video - this is a straight photo I took last weekend where the same error showed up).

In the photo I'm shooting with the 24-105 at an F4 - 1/30 - gain of 2500 (I think - going from memory here). As you can see several of the lights are purple instead of white. Even the reflection in the water is purple.

In the second photo, this is an absolutely new problem, and a bit of a disconcerting one because I've never seen it before. I was videoing the sunset from a boat, and this bizzarre spot showed up in the center of the sun. I was using the 24-105 and was using a vari-ND.

The reason I post these two pictures together is I'm wondering if they're related in anyway. Anyone ever experience anything like this or know what it might be? Thanks in advance.

I had this effect last year. Not in every flash of the lights, but in most of them

If I remember well, Canon released firmwares that fixes this kind of problem in the past. I could be wrong.

I believe that the very first firmware update for the 5D2 dealt with the "black dots on highlights" issue. It should be a thing of the past.

Regarding purple and green fringes, that's usually a lens issue and could also be caused by the vari-ND.

Indeed it should Jon, and I got that update. However, this was shot about a year ago and clearly it isn't fixed. Funnily enough, I thought it was fixed, because some theatre work I did after the update was dot free.
But how could it come back?
Vey odd.

I shot a major label music video last October with Firmware 2.0.7 with lights in the frame pointing at the lens for intentional lens flares at the request of the director, and I had black dots. We simply ignored it on the day and removed them in post. But we shouldn't have had to do this. Canon should fix this problem once and for all. If the sensor is hit with bright light that clips, it should simply go white. Period.

Do I remember rightly. Didn't the RED have a little red dot in the middle of highlights for a while? Did they fix that?