Only a day before a scheduled settlement hearing, a U.S. judge has recused herself from overseeing a lawsuit against Facebook. She has yet to explain why.

U.S. District Judge Lucy Koh in San Jose, Calif., announced yesterday that she was stepping away from the suit that involves Facebook’s “Sponsored Stories” section. Five Facebook users had sued the social network last year claiming it violated their privacy rights by displaying users’ “likes” of certain products or companies without their permission. The suits, which had sought class action status, had a potential of 100 million class members.

In the proposed settlement, Facebook agreed that users would have more control over the information the social network used about them. The social network also agreed to pay $20 million to settle the case, court documents said. However, a judge must approve the settlement.

Koh had overseen the case since plaintiffs filed it last year.

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