How is the standard profile orientation defined?

[tvbn]

Hi all,

I am assigning profiles to curves in bulk, and am wondering why some of the profiles are flipped by a certain degree. I have an example in the image below. I'm really racking my brain as to why this is happening, as it requires me to suddenly estimate/calculate and apply an orientation to some of the beams, which is not possible for my application. I already checked if it was due to the direction the curve was in, but that unfortunately was not the case.

I saw that this happens consistently for more beams (see last image), so I suppose there is a pattern in there.

Thank you very much!