why does STAAD consider beam nodes during Torsion Check?

I am trying to do a torsion check in a steel beam with 2 nodes in the span where perpendicular beams are present and pinned supported (MY & MZ released) at the end. When Member load concentrated moment loads (CMOM) are applied with respect to the middle beam segment, the torsion check results are only available for mid-segment only. For the other two segments, STAAD output has a warning that states "Torsion design of member # not possible as it has no torsional force/stresses". PMEMBER command has also been used to tell STAAD that it is a single continuous beam, but the results are the same.
Only when the nodes are removed manually and made the beam with no nodes between the end supports, the results seem to make sense for that beam.
Could someone let me know why STAAD takes such nodes into consideration even though these nodes do nothing (nor resist torsion or help in torsion) and provide results for a small span only and not as a single beam even though the segmented beams are grouped as a single beam?