The document says that "lineParam" is the parameter that represents the ratio along the line segment at which the nearest point is found. However, in the implementation, "lineParam" is actually the signed distance between the projected point on the segment and the point "a".

Either the document or the implementation needs to be changed.

If the implementation is to be changed to conform with the document, I suggest using the alternative implementation attached to this report.
This implementation avoids using "math.length" for performance reason.

Keep in mind that the "SplineMath.PointLineNearestPoint" is used elsewhere in the package, so the special attention to the method's references is necessary.

Reproducible with: 2021.3.14f1

Reproduced on: Windows 10

Note: CQA testing is not required, leaving the description of the issue as is