I've actually had issues with STLs generated with OpenSCAD more than Fusion; to a point where I've had to import the OpenSCAD code into the FreeCAD OpenSCAD mod

I've actually had issues with STLs generated with OpenSCAD more than Fusion; to a point where I've had to import the OpenSCAD code into the FreeCAD OpenSCAD module and use FreeCADs STL export to get it working. 99% of the time I don't have to deal with that, but that 1% is pretty annoying.