Curves consist of linear segments. The styles of SketchUp do not display on very small entities or short edges, because otherwise (and due to the thickness of sketchy lines) most of the model would be covered with sketchy lines. Now the issue is that after editing an arc or circle or polyline with pushpull or other tools, it is converted into normal edges. Very short edges, so the sketchy lines don't appear. If you zoom in, they should appear again.
I think a solution would be to convert the single edges back to one "polyline" entity so that SketchUp knows they belong together. There is a plugin that can do this. If you like, you can download it from the link below and drop the *.rb file into the SketchUp\Plugins folder.