You shouldn’t worry about the small difference as the errors are in the range of the limited floating point precision.
These small absolute errors are created by e.g. different ordering of your operations as seen here:

x = torch.randn(10, 10, 10)
s1 = x.sum()
s2 = x.sum(0).sum(0).sum(0)
print((s1 - s2).abs().max())
> tensor(2.3842e-06)