The flickering is directly related to the ISO, picture profile, and, to a certain extent, the white balance. DJI seems to have screwed up on the way gain is used to increase exposure, so black levels flicker and increasing the ISO allows you to see the flickering. The Log profiles also unnaturally raise the black levels and allow you to see the flickering at lower ISO levels than the None profile. The X5 has a natural white balance near to daylight, so if the white balance compensates for tungsten light or other light colors, it raises the gain on certain color channels and the flickering becomes pronounced at lower ISO's. It's best to keep the ISO as low as possible when shooting objects with alot of blacks. You might not actually notice the flickering at 3200ISO as long you don't have any noticeable blacks in the lower 15-20% IRE. I would say the best settings are to shoot at None, 800 or less ISO, and daylight if possible. Do not underexpose, though, as that will just make the flickering more noticeable.