Traditional weak point of CR / Lightroom is the noise reduction. I found similar problems reported to Adobe 2 years ago but nothing has been improved. The noise removal and sharpening should be split between dark and highlight areas. It is obvious taht the noise is much more visible in dark areas of photo. The sharpening and the noise removal should be split into separate areas: dark and light. It should be really easy to implement basing on local corrections with luminocity range.