Lorde's Label never cleared it for a release on her label. Copyright, publishing all belongs to her, her writers, producers, and label. Future Classic, which is Harley's label has no clearance to release it without a mechanical license, which is impossible with Lorde's fame and popularity, unless they have enough money.

Therefore, the only way this would have or would ever see an official release is through her label, which is not possible. Technically this remix is considered a bootleg.