The plotting algorithm used to NOT plot failed elements in
ANSYS LS-DYNA 8.1 seems to be broken. Is this a known error?
Yes. Defect 24646 was filed and corrected in ANSYS LS-DYNA 9.0.
The workaround is to use LS-POST to postprocess the results.
Please note that it is only the plotting algorithm that is incorrect
in ANSYS LS-DYNA 8.1. The correct elements are being deleted
from the solution calculations, as required.