How did you save the model?
This workflow works for me:
In PyTorch 0.3.1.post3:
model = nn.BatchNorm1d(3)
torch.save(model.state_dict(), 'test.pt')

In PyTorch 0.4.0:
model = nn.BatchNorm1d(3)
model.load_state_dict(torch.load('test.pt'))
x = torch.randn(1, 3, 2)
model(x)

Did you save the complete model rather than its state_dict?
If so, you should get a warning:

SourceChangeWarning: source code of class ‘torch.nn.modules.batchnorm.BatchNorm1d’ has changed. you can retrieve the original source code by accessing the object’s source attribute or set torch.nn.Module.dump_patches = True and use the patch tool to revert the changes.