>I would summarize what is occurring not as a bug but a different response of the inaccurate Develop-Fit rendering to a different coarseness of noise that is caused by an extreme setting of the Lum-NR-Detail slider.
Yes that was my guess too. This is likely an artifact of the Develop-Fit view rendering algorithm that is amplified by extreme noise reduction settings. Not a bug but you could call it a design flaw that can't be fixed without breaking other things, most notably causing large impacts on the programs speed.