The Floor I use for my slab-on-grade is muti-layered and shows the concrete slab and the gravel base beneath it (and occasionally the amount of compressed soil as required by our soils report).
I want to use a Slab Edge to create a standard haunch along the edges. But when I use the OTB Profile for this the gravel base cuts through the Slab Edge. At first I thought it might have something to do with the layer function (structure, finish, substrate, etc.) but I've been testing different options and haven't found anything that works.
I've attached images of what it looks like before and after you join the Floor and Floor Slab edge.