Here's the deal: there's this thing called "pulse width modulation," and under certain conditions it doesn't play well with rolling shutter cameras. Most of the time it's no problem, but we don't get phone calls from post when there's no problem. Here's how to avoid that phone call.
I recently shot a quick project for a major cell phone manufacturer and while lighting "phone in the hand" product shots with a somewhat uncommon LED light I discovered dozens of little roll bars in the image. The roll bars only appeared if the LED light was dimmed. I've written about this kind of roll bar issue here, but only when dealing with discharge sources powered by failing ballasts. There was nothing wrong with this light, it worked exactly as it was supposed to.
This rolling effect is the result of shooting a flickering light source with a rolling shutter camera. It's not something that can be fixed in post. I reproduced the effect later with my Nikon D7000, using the same light and shooting a test chart in my spare bathroom (the only light-tight place in my home during the day).