Welcome to the forum.

What happens is that some reference planes are intersecting that surface twice, due to the return in the curvature. Also, I see that you want that distance between the blue lines on your sketch to reduce gradually, at every step. That is possible, but it's not simple, and its not possible with a pattern-based grid, but with repeaters and repetitions. It needs a formula to reduce the distance between those "blue lines" along the curve, gradually, in order.

Search this forum for "progressive spacing", to get an idea.

One hack would be to break the mass into two different parts.

I would do that by making the mass and then adding a void to delete one part once and making that as one file. Then do the same for the other part and save that as another file. The pint of cut should be one surface division. Then, I would add surface intersects in each file and bring them together in a new file and join the object at the cut line.

It is not an elegant solution and requires 4 files to make the mass
1 original mass
2 files for the 2 parts with voids.
1 file for joining the split mass

however, it is way I discovered that works.

I did something similar when I wanted to make a surface with part curtain wall and part brick. Check out my website link
Projects - Lakshya BIM Outsourcing Services
click on custom modelling
go to adaptive components and curtain panels
look for compound facade.

hope that helps.

What?