Hi Epics.
Is it bug or feature?
Whenever I try to make vertical loop, spline component twists in that point and upper part goes up side up (and not upside down as expected).
Is it desired behavior? Looks like some spline component limitation.
with no node rotation I am able to produce desired behavior 
Hi Yata,
You just need to play with the Spline Up Vector values until you get something that works. Here is a bit more info on them, it was called Spline Up Dir in that post.
Let me know if that helps.
Cheers,
TJ
Looks like that method would not work if i had some spiral or S shaped figure.
Dividing spline to different parts can help, i think.
Still interested why splines made that way. It should be not very complex to interpolate node rotation on patches.
Ive suggested to others to perhaps try to use 2 splines if you want to control the orientation. One spline controls the position as you have but the other lets you control the direction of the Up Vector (rotation/twist/etc).
Playing with that value only moves the problem to a different part of the spline.