The capx isn't complicated at all
The issue actually happens with your demo as well (http://dl.dropbox.com/u/36472942/construct/plugin/release/pathfinder/demo/index.html)
If you click and drag either the S or D around, it works fine. But if you're dragging the S and it moves over the D, they will both lock together because the project will register your mouse being over both the original sprite and the one you're moving over.