Rotate copies corrupts document

Steps to reproduce:

Draw a curve, apply Rotate Copies, save.

What happened?

Broken SVG

    <inkscape:path-effect
       split_items="false"
       mirror_copies="false"
       copies_to_360="true"
       Gap space between copies, use small negative gaps to fix some joins="0.05"
       rotation_angle="60"
       starting_angle="0"
       num_copies="6"
       method="normal"
       is_visible="true"
       id="path-effect1412"
       origin="0,0"
       starting_point="0,0"
       effect="copy_rotate" />
  </defs>

Maybe this line should be

gap(_("Gap"), _("Gap space between copies, use small negative gaps to fix some joins"), "gap", &wr, this, 0.05),

What should have happened?

Working SVG

A manual edit in text editor fixes the issue.

Inkscape Version and Operating System:

• Windows 10 x64
• Inkscape 1.0 Beta 1

corrupt.svg