Rotated Perp Frame issue and Misc. Error

Hello, my problem right now is two-fold.

My first issue is that the final few perp frames I generate in my script are rotated (see image). The fraction of rotated perp frames is around 1/10 of the total number of divisions of the lines that form the railing. The rotated perp frames cause the box extrusions I create to be rotated as well, which is an issue.

My second issue is that my goal with this script (attached) is to use a curve as a railing instead of a straight line on one side. However, when I replace LineA with CrvA in my script, the resulting form is a skewed mass of boxes instead of a row of boxes that follow CrvA (see image)

My guess is that the second issue is caused by something related to the first issue. Does anyone have a guess as to what may be causing these issues?