Wall layers not exporting - IFC Model Exchange with Archicad for Revit

[Rik McKenzie]

Wall layers from the Revit file won't export regardless of the options selected in the exporter.

I have also tested with multiple versions of the IFC exporter for Revit which the Graphisoft piggy-backs their exporter on.

The guide clearly states that ticking the "Parts as building elements" box will seperate the layers (see Export Guide attachment).

I have attached some screenshots showing the layers in Revit, then the lack thereof in multiple IFC viewers and Archicad 25.

Can someone please help diagnose why this might be happening?