All keys remain gray or completely colored (when you set the option to ‚Color all keys‘). In the desktop view of Traktor everything is correctly displayed and working. I have tested this several times and also found YouTube comments that say the same thing.
I have tested it on Traktor 3.5.2.299 and Traktor 3.6.0.325. On a Traktor Kontrol S8 and S5 and on Windows 10 and Windows 11.