Lavender Brown
Played by Kathleen Cauley in the second film (non-speaking part, but the actress is credited as Lavender):
[img: Lavender Brown, a dark-skinned girl with short black hair, wearing earmuffs while working with mandrakes in herbology class]
Played by Jennifer Smith in the third film, again in a non-speaking role:
[img: Lavender Brown, a dark-skinned Gryffindor student with short black hair, clapping during Dumbledore’s speech at the beginning of the school year]
In the later films, when she gets a considerably larger part and dates a member of the main cast, she’s played by Jessie Cave:
[Lavender Brown, now suddenly a pale-skinned girl with long dark-blonde hair, writing in a notebook]
So yeah. This is a thing that happened.
Ugh. What else is new?
I forget who I was arguing about this with, but they were wholeheartedly trying to convince me that Lavender Brown had always been White.