It is strange that it breaks the lines in the first place... I wonder why they decide to do that?

They may process Line entities instead of Spline entities better. There are a lot of different ways to store stuff in a DXF file, right now that converter just exports everything as a Spline object, but for version 2 I want to add an option to output stuff like line, circle, and arc entities instead of everything as a spline. That might help for some situations.

- Michael