I'm using fc31 with zawertun copr repos for plasma 5.17.4. In systemsettings/fonts the default setting is: antiAliasing: enable sub pixel rendering: RGB hinting: slight But, after logoff/login, plasma is using only grayscale subpixels. RGB works, if you do the following: - open dolphin systemsettings/fonts/choose subpixelRendering 'none', apply (warning: changes only for newly started apps) systemsettings/fonts/choose subpixelRendering 'RGB', apply (warning: changes only for newly started apps) open a second dolphin window ZoomIn, and compare dolphin1 (using grayscale) with dolphin2 (now using RGB subpixels) font renderings. Logoff, re-login, and all is back to grayscale only, RGB has been 'forgotten' although the settings panel still shows RGB as being the active setting.
*** This bug has been marked as a duplicate of bug 416140 ***