According to a report by Yahoo News UK, Rakhee Thakrar confirmed her exit from the cast of "Sex Education" in the issue of the Daily Star Sunday paper published in England on July 31. Thakrar didn't state a reason for leaving "Sex Education" prior to its fourth season, leaving the exact nature of her departure unclear.
"I'm not part of the new series. I can't really talk about why," Thakrar said. "But I'm so proud of the show and grateful to have been part of something so important. There is nothing bad about 'Sex Education.'"
By contrast, Patricia Allison explicitly named new work opportunities as the principal reason for her departure, whereas co-star Simone Ashley, who's also leaving "Sex Education," told This Morning in so many words that her role in "Bridgerton" conflicted with her return. According to her IMDb profile, Thakrar will appear in three upcoming projects, including the Timothée Chalamet-led "Wonka." While this and both of the other future works in which she will appear are in post-production, it's entirely possible that commitments relating to "Wonka" or even a yet-to-be-announced project precluded her from returning to "Sex Education."
According to the Film & Television Industry Alliance's productionlist.com, "Sex Education" Season 4 began shooting on July 4, so more information about the upcoming, Thakrar-less season may be imminent as its production progresses.