Just train the model on other races, what’s the problem?
See "fewer than five complaints" on the third/fourth paragraph of page 21 of this letter Proctorio sent to the senate [0].
From anecdotes from my circle of friends alone, I've heard at least 3, some correlated by race, and then seen many tweets from @Procteario about it, so I didn't buy it, ran it myself, and tada. bias.
Also, it's less of a "just train" problem and more of a "complete redesign" problem - HAAR cascades use greyscale images, which generally mean a loss in contrast and makes it difficult. You'd likely need a full color oneshot network, such as BlazeFace, to make it work.
[0] https://epic.org/privacy/dccppa/online-test-proctoring/Proct...
However, now that we know what the issue is, ongoing inaction is racist.