Digitising Kodachrome ... colour adjustment with Darktable

I was referring to the difference between say, full spectrum white light, and narrow band rgb lights, of which there is some debate which is best. In many cases yellow and orange may prove most problematic, which could perhaps explain why your grass goes from green-yellow to green-blue. Just one of many possibilities. See @NateWeatherly graphs here: Digitizing film using DSLR and RGB LED lights - #5 by Thanatomanic