Default element sorting for 3-noded shell elements uses the collapsed BT formulation which is not recommended but is maintained for backward compatibility. The first option that LS-DYNA offers is to sort these elements to use a C0 triangular shell formulation which may provide better answers than the default formulation. LS-DYNA 971 (R3 and later) now offers the sorting to use a DKT formulation that shows encouraging results for crash analysis. You can read the original paper (PDF) for more information. You can invoke the DKT sorting by setting the ESORT=2 in *CONTROL_SHELL keyword.