I realize that this will probably be down to the configuration of OpenCascade itself, but the STEP file exported from the "Simple vase" example is for ISO 10303-214. This standard has been withdrawn and applications should use ISO 10303-242 instead.
FILE_SCHEMA(('AUTOMOTIVE_DESIGN { 1 0 10303 214 1 1 1 1 }'));
FILE_SCHEMA(('AP242_MANAGED_MODEL_BASED_3D_ENGINEERING_MIM_LF {1 0 10303 442 1 1 4}'));