I downloaded the image and viewed it in photoshop and even with contract and brightness adjusted all the way to the extremes I couldn't see the lines you are talking about. There may be some noise in the blacks but otherwise no I couldn't see anything.
How are you converting or are you editing the h.264? If you are on a Mac, try converting with the free version of 5DtoRGB to ProRes. The program has an algorithm that will help clean up lines if it is a sensor issue.