12. EXO Corporation, Inc. (ECI) and its exclusive bargaining agent Kami Labor Union (KLU) entered into a collective bargaining agreement effective from December 15, 2019 to December 14, 2024. The agreement prohibits KLU and its members from holding a strike and lockout. In May 2024, ECI and KLU negotiated the economic provisions of the agreement but ended in a deadlock. KLU filed a notice of strike. After the conciliation failed, KLU conducted a strike vote which obtained majority support. KLU reported the strike vote to the Department of Labor and Employment. KLU then went on strike after the mandatory cooling-off period. ECI questioned the validity of the strike for being contrary to the collective bargaining agreement. In contrast, KLU argued that it complied with the strict requirements for staging a strike. Is the strike legal? Explain.