Curve segments with arrow ends have their nodes inside of the arrowtriangle while line segments have them at the tip of thearrow. Converting a line segment into a curve segment will thusrearrange the segment erroneously.
You might post a CDR example to help explain that. I believe you but examples assist in action. See if you can show why it's not only wrong but an issue of concern.
Tried to make clear what I mean in the attached file LineVsCurveSegment.cdr. This missbehavior traces back to CorelDraw6 at least.