Mattel Inc.’s trial loss in its eight-year fight with Bratz doll maker MGA Entertainment Inc. was questioned by the same federal appeals court panel that two years ago threw out Mattel’s earlier victory over its rival.

The three U.S. Court of Appeal judges, at a hearing Monday in Pasadena, Calif., challenged MGA’s lawyer Clifford Sloan on how the toymaker could have brought its trade- secret theft counterclaims, on which it won $160 million in compensatory and punitive damages, into the case in 2010, six years after Mattel said MGA should have known of the alleged thefts.