Export 3d cad file, funky results

hi all
i drew stairs with a balustrade in a project
the stairs go 3 floors up, and some copying has been done
happy with the result, i want to ask for quotes and thus export the sd file to dxf
only to find a dxf file where the stairs have ‘randomly’ been copied a few times more, and the balustarde floats somewhere in space nearby
any suggestions?trappen.skp (260.7 KB)
trappen.dxf (1.6 MB)