CoP in B3D files doesn't match GUI or raw mot files.

[THEONE-1]

I'm retrieving CoP of this trial from downloaded b3d using cop = [frame.processingPasses[0].groundContactCenterOfPressure for frame in subject.readFrames(xxx)] The retrieved anterior-posterior CoP (x-axis) values don't change along with the foot segment. However, in GUI or raw mot files it looks noisy but normal.

I looked into a few Carter dataset b3d files already and they all have this issue.