Noise/grain is added to my 4K video when I export AE comp using Media Encoder! Do you guys know why?

Hi, i tried to export a After Effects  4K comp using Adobe Media Encoder but after rendering the video has a red-brown grain/(kinde of noise) it doesn't look like the original video !  ( I shot few  time lapses at different places  with Panasonic GH4 , I then imported the RAW files into After Affects 4k comp, I added some layers for color grading and a background song I used Media Encoder to export the 4K comp in H264 at 96mbps checked ''use maximum render quality''  waited few hrs and when I played back my video it doesn't look like the original video, I also did few tests using different formats (PNG or H264 at lower mbps) but still get the same bad video ... I used a small clip from the timelapse and I still get that kind of grain or blury/grain/noise effect on my video, I checked the effects settings and there's no LUT or effects  selected I still don't know why I get that ? I would like to mention that when I exported the comp in 1080 hd from AE (quicktime H264)  the video looks fine ...I only get that when i try to export time lapse comp in 4k . Do you know why? what do I do something wrong? what is the right way to export a 4k time lapse from AE ? I intend to upload it to you tube. Thank you !