Hi Andrei - it's intentional for surfaces built from joined curves to have the same segmentation structure of the curves. That's just what makes things the most predictable, that the surfaces that come from a curve should inherit the same structure as the curve.

If you want the surfaces to behave differently than the curve then you would need to edit the curve to form it how you want.

In the future I do want to make some kind of option within Join for deciding whether to fuse segments together into single longer segments or whether to keep them as independent segments. I'm not exactly sure yet how that will work, it may involve making Join have extra steps in the command which can sometimes be awkward to deal with.

- Michael