Hi,
I assume you tried most settings so i Duplicated and Edited the Existing IFC4 Reference View (Structural) Export Setup in Revit 2023 and set the Level of Detail to High - (I don't have time to test low but though you would have used this by default anyway)
Opening the IFC back in Revit included the Filet (I created using the Steel Tab > Notch Tool)
This was also the case for Navisworks too.
Jay Colcombe
Autodesk Certified Instructor
Revit Architecture & Structure Certified Professional
AutoCAD Certified Professional
B.Sc. Hons Civil & Structural Engineering
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