A fun fact for folks using Fusion 360: Setting your tolerance too loose can prevent G2/G3 paths in post.
Turns out if your tolerance is too loose, it can cause the post processor to not recognize circular features as…circles. So it generates linear commands instead of G2/G3. If that happens to you, try tightening up your tolerances/smoothing.
I think this post on the Autodesk forums describes the issue: Post-processing 3D contour as G2/G3 (arcs) is not working on a large stock - Autodesk Community
That was a fun bit of emergent behavior to discover in fusions post processor 