I have the save file if needed (no screenshot but can provide one if needed).
An Iron and Sand “node” spawned overlapping each other. I hadn’t planned on using either as a future mine (due to layout/design), and was using the flatten terrain tool to ease the slope where they are located.
At a certain point the layers split (visually) and the the sand was suspended above the terrain (roughly the height of in-game person).
Further flattening tool use has resolved this, but maybe a tweak to node proximity or terrain rules could prevent this?