There are some misunderstanding in the definition of the neutral line of the flex witch ends in different flex length of the unfolded flex.
Definition: neutral line is the center-line of flex stackup
Mentor: assumption that the Neutral Line is on the inside board surface of the bend
I have placed on the IDEA platform a idea to correct this feature.
To get a quick solution I beg everybody to join this IDEA platform to set the priority for the ideas.