Slope to Target not creating 2D element

When using "Create 3D by Slope to Target" in order to model the interface to a construction terrain the 3D element is created, but there's no equivalent element created in the 2D display.

It's not the end of the world, I can work with the 3D element for creating the design surface, but I've not seen any other linear element not have a 2D equivalent, and I've tried multiple features.

I'm doing it this way because I can't find any way to create the interface of two slopes, or to add the construction surface to the interface point using Alternate Surface in the template editor (and there's several terrains in the model that could be listed, but there's none.

Using ORD 2021 R2 U10 (10.10.20.78)