input_unfold and weight_flat are as given below.

input_unfold =  tensor([[[[0.0000, 0.0000, 0.0000,  ..., 0.9194, 0.0503, 0.9589],
          [0.0000, 0.0000, 0.0000,  ..., 0.0503, 0.9589, 0.6398],
          [0.0000, 0.0000, 0.0000,  ..., 0.9589, 0.6398, 0.0000],
          ...,
          [0.0000, 0.7830, 0.6963,  ..., 0.0000, 0.0000, 0.0000],
          [0.7830, 0.6963, 0.6662,  ..., 0.0000, 0.0000, 0.0000],
          [0.6963, 0.6662, 0.8015,  ..., 0.0000, 0.0000, 0.0000]]],


        [[[0.0000, 0.0000, 0.0000,  ..., 0.7274, 0.0721, 0.7137],
          [0.0000, 0.0000, 0.0000,  ..., 0.0721, 0.7137, 0.8258],
          [0.0000, 0.0000, 0.0000,  ..., 0.7137, 0.8258, 0.0000],
          ...,
          [0.0000, 0.1822, 0.6842,  ..., 0.0000, 0.0000, 0.0000],
          [0.1822, 0.6842, 0.2491,  ..., 0.0000, 0.0000, 0.0000],
          [0.6842, 0.2491, 0.4927,  ..., 0.0000, 0.0000, 0.0000]]]],
       device='cuda:0')
weight_flat =  tensor([[[ 0.0389],
         [-0.0168],
         [ 0.0396],
         ...,
         [ 0.0852],
         [ 0.0824],
         [ 0.0089]],

        [[-0.0027],
         [ 0.0509],
         [-0.0628],
         ...,
         [-0.0616],
         [-0.0226],
         [ 0.0380]],

        [[ 0.0298],
         [-0.0171],
         [ 0.0830],
         ...,
         [ 0.0128],
         [-0.0004],
         [ 0.0607]],

        ...,

        [[-0.0579],
         [-0.0283],
         [ 0.0257],
         ...,
         [-0.0370],
         [ 0.0655],
         [ 0.0790]],

        [[-0.0675],
         [ 0.0641],
         [ 0.0404],
         ...,
         [ 0.0852],
         [ 0.0168],
         [-0.0272]],

        [[ 0.0215],
         [-0.0780],
         [-0.0812],
         ...,
         [ 0.0270],
         [ 0.0331],
         [-0.0470]]], device='cuda:0', grad_fn=<ViewBackward0>)

input_unfold.shape =  torch.Size([2, 1, 135, 225])
weight_flat.shape =  torch.Size([32, 135, 1])