Not easily in the current version.
This operation creates a polyline (which is why there are additional nodes).
If you don’t want them you will need to either re-create the geometry (pretty easily done for circles/rectangles/regular polygons), re-draw it, or perform the operation in a 3rd party tool which does not take this approach (export, offset, save, re-import).
As noted at:
the polylines are quite close to the ideal path, so shouldn’t be an issue — if you have a file in which they are, let us know and we will look into this with you.