Did you read the ingredients? Non-greboks means wheat free. Chabad and others don't use any product that would involve mixing water with matzo (wheat) on the off chance that some of the wheat wasn't mixed well and might rise. Gefen is a reliable company. I don't think they would lie . You could email your question to the certifying agency. Also, kashrut.com puts out alert lists, and they links for passover info, sodas, slurpees, etc.