getProjectCone dereferences the pointer to the projection cone. Apparently, it happens that this pointer points to an invalid address even if ProjectCone is marked as computed.

import PyNormaliz
NP = PyNormaliz.NmzCone(['vertices', [[0, 0, 1]], 'cone', [], 'subspace', [[2, 2]]])
PyNormaliz.NmzResult(NP,"ProjectCone")