We’re at 1.3.1 now  I just tried again with latest version and it works:
>>> a = torch.rand(2, 4, 4)
>>> a.triu()
tensor([[[0.6312, 0.0578, 0.9598, 0.4663],
         [0.0000, 0.3202, 0.9285, 0.6618],
         [0.0000, 0.0000, 0.4512, 0.0584],
         [0.0000, 0.0000, 0.0000, 0.2116]],

        [[0.1818, 0.8329, 0.9879, 0.6801],
         [0.0000, 0.2870, 0.3073, 0.3876],
         [0.0000, 0.0000, 0.6292, 0.7130],
         [0.0000, 0.0000, 0.0000, 0.7048]]])