As if Groupon didn’t have enough troubles: The daily-deals company is facing yet another class-action lawsuit, courtesy of San Diego-based law firm Robbins Geller Rudman & Dowd LLP, which previously sued Groupon in the spring. The class action is on behalf of Groupon common-stock owners during May 14-Nov. 8. “The complaint charges Groupon and certain of its officers and directors with violations of the Securities Exchange Act of 1934,” according to the firm. “The complaint alleges that during the Class Period, defendants issued materially false and misleading statements regarding the Company’s business and prospects.