Standard gamma uses photo picture profiles which may cause the problem? So I would test with Gamma D or Gamma C. Also it has been speculated that 4096 mode is just upscaled 3840 (becouse 4096 is softer than 3840) so maybe upscaling causes other issues as well. I personally use 3840x2160, 25p, Gamma C, 0-255, sharpness -10, green x0.95, PRO bitrate, and I haven't had any issues. Sidenote: converting to ProRes (at least with Rockymountains Movie Converter) adds banding, while converting to H.264 wont.