In AUPE v Alberta, 2014 ABCA 43, the Alberta Court held that the essential character of a dispute between the parties was beyond the jurisdiction of a grievance arbitration board where it involved the constitutional validity of s 12(1) of Public Service Employee Relations Act. The dispute at issue raised the question whether, as a matter of constitutional law alone, an entire group of workers was wrongly excluded by the statute from the bargaining unit. It was not a dispute under the collective agreement.