complex value for shape feature elongation and flatness which involves two PCA components

Operating system: OS
Slicer version: not about slicer
Expected behavior:
Actual behavior:
I extracted from some dcm slices and corresponding masks via pyradiomics package, the puzzle is that I got some complex values such as 0.9999e10-12i, I searched the feature names whose value are complex values. all of them is involved in the two components from pca, some for the major and minor, component,while some for the first and second main component after pca. Do anyone get any idea about this situation? thanks for any attention