Joint wall and floor are different in 3D vs section 2D

[ryley.g.h]

Hello, got an odd one here. See attached images.

The section is a straight cut, no over-rides, no detail lines/regions. Notice how the gravel is on the inside of the concrete wall, which is exactly how it should be. However, in 3D the gravel goes to the outside, and it's messing up the 3D views, and elevations!

It's a phased project, the white blob is the topo set to existing, and I added transparency on the 3D for clarity's sake. The floor and wall are both set to new construction.

Is the paint tool my only option?

[bin]

It's probably because Revit uses the bottom level material of a floor for the side.

The easiest way to fix it is to paint the side using the top material (concrete).

Or model 2 floors, 1 with only the concrete layer, and the other with the sand and gravel.

Or add a 0 thickness membrane layer with concrete material, saw this one somewhere but haven't tested.