Hi Mikael
Unfortunately, this is a known problem at the moment. The workaround until this is fixed is to use the hardscape tool with NO joint pattern set and then place a polyline with the correct hatch in the annotations of the viewport. This way, your hatches can be the correct scale, but you can still retain all the other benefits of the hardscape tool (hiding and showing edges, clipping areas and having edges on those, creating pads on terrain or textures beds, etc...)
Hope that helps.
Tamsin