So, I'm not sure how best to report this (there is noone to email, and I don't see how a git pull works for this), but there is a typo in the documentation.
Specifically, in the documentation for color space conversion from BGR to LUV, the piecewise formula for the computation of $L$ in COLOR_BGR2LUV should be $116Y*{1/3} - 16$, and the subtraction of 16 is missing.