The Red Digital Cinema camera uses a CMOS sensor with a rolling shutter. One of the criticisms of the camera is the fact it is subject to rolling shutter artifacts in some situations. Now, I should note that I am not bashing Red…to be clear, every camera has limitations. Even film cameras can exhibit shutter-related artifacts. The important thing is to arm yourself with knowledge, so you know how to avoid situations which will stress the equipment you are using.
To that end, here is a little background info on Red’s rolling shutter: Understanding Rolling Shutter Artifacts.
That link talks about the design of the shutter and how it operates. It also offers a few suggestions for minimizing the effect. And if you’ve never seen the effect, here’s a video that shows the split-screen-strobe issue pretty clearly. More discussion at Reduser.