Why is Sam’s hair brown in Dream Warrior and then blond in No Mercy? Angelia’s hair does the same thing too.
These aren’t discrepancies. As in the real world, the characters change year to year. Some of them such as Acheron, Simi, Savitar, Xirena, Zeke, etc. don’t have a “set” human form. They can be any height or hair color or eye color they choose and they vary it just to mess with people’s perceptions. Others such as Stryker, Samia, Angelia et al partake of hair dye and haircuts.
It’s usually a year’s span of time between books and it may be several years before a character is seen again. In that time, they can and do get haircuts, change hair color and other such physical matters. In some cases such as Fang in Bad Moon Rising and Wren in Unleash the Night, the changes are shown on screen. But in others such as Sam in Dream Warrior, they get their hair done off camera. My real hair color is jet black and extremely curly. Most of you have never seen me with black hair and the red I choose varies all the time. Likewise, I often blow my hair out, but other times leave it curly. The characters are the same way.
Lastly, I write in what’s called deep character POV. Therefore, when you’re getting a description of a character, it isn’t always consistent with the last person’s POV you read from. Case in point, I always describe my brother as blond. Yet I’ve been corrected many times by others who call if brown. In my family of jet black hair, his hair is considered blond. Height and petite are also in the eye of the beholder. Acheron considers Tory petite and tiny even though she’s over six feet tall, because compared to him, she is. It’s why Nicolette seems different in Unleash the Night. Wren is the first character who describes her who doesn’t love her. He’s suspicious of her.
None of this is done out of author forgetfulness or lack of care on my part. It’s done intentionally to add realism to the characters and books. It’s now been over ten years since the first DH book came out. It would be weird and unreal if none of them had ever changed in the last decade. Think of it like the way TV show characters change season to season.