On the 10 III R and B diodes are dark while green is very bright. So it actually “eclipses” (or rather overshines) the other two, resulting in wrong colors. Colors produced by combinations of red and blue (which have approximately the same brightness) are correct, for example magenta #ff00ff looks kind of OK. But if the bright G component has to be used, it is way too bright and outshines the others, so you get wrong color. Hence you can’t even get a clear white from #ffffff because there’s too much of green in it. You can try to set a darker value for G diode giving lower brightness similar to the strength of R and B diodes, but it gives acceptable results only for some colors.
Maybe it is an electrical problem - either the G diode is fed with too high current, or the R and B diodes get too low current.
Compared to this, my XA2 Ultra LED gives very nice, correct and clear colors.