The plain Python code calculates:
-(0.9955 ** 0.0448)
> -0.9997979654463205

While you are trying to calculate
(-0.9955) ** 0.0448
> (0.989911956308302+0.14025081271947198j)

in PyTorch, which is a complex number.
If you want the first output in PyTorch, just use:
-1.0 * torch.tensor([0.9955]) ** torch.tensor([0.0448])
> tensor([-0.9998])