Here my wild speculation about the psychology of a fictious character that is not even a whole character but just a painting...
My guess is she feels not attractive enough and thus tries hard to look feminine and enhances that by bleaching her hair in the attempt to look more like the beautiful Crane maidens... after all they are known for their beauty and every Emperor is marrying a Crane.
But I would not mind if it is actually a guy who feels feminine and thus goes with that gender representation.
Either way, I see no big deal about it. L5R has a long history about gender representation questions, that some people thought Kachiko was over sexualised, or that Hitomi was not feminine enough and so on. So, why are so many trying to ruin those interesting and flavorful characters by pressing them into gender expectation boxes? How about we enjoy the diversity the setting offers instead?

