Stack trace encountered when staging a tarball

So far this is an incident, not sure how to reproduce:

[00:01:15][67f528b9][build:core/adwaita-icon-theme.bst   ] BUG     gnome/core-adwaita-icon-theme/67f528b9-build.15748.log

    An unhandled exception occured:
    
    Traceback (most recent call last):
      File "/codethink/GNOME/buildstream/buildstream/_scheduler/job.py", line 265, in child_action
        result = self.action(element)
      File "/codethink/GNOME/buildstream/buildstream/_scheduler/buildqueue.py", line 34, in process
        element._assemble()
      File "/codethink/GNOME/buildstream/buildstream/element.py", line 1074, in _assemble
        self.stage(sandbox)
      File "/codethink/GNOME/buildstream/buildstream/buildelement.py", line 177, in stage
        self.stage_sources(sandbox, self.get_variable('build-root'))
      File "/codethink/GNOME/buildstream/buildstream/element.py", line 481, in stage_sources
        self._stage_sources_at(host_directory)
      File "/codethink/GNOME/buildstream/buildstream/element.py", line 1406, in _stage_sources_at
        source._stage(directory)
      File "/codethink/GNOME/buildstream/buildstream/source.py", line 316, in _stage
        self.stage(directory)
      File "/codethink/GNOME/buildstream/buildstream/plugins/sources/tar.py", line 78, in stage
        tar.extractall(path=directory, members=self._extract_members(tar, base_dir))
      File "/usr/lib/python3.5/tarfile.py", line 1998, in extractall
        numeric_owner=numeric_owner)
      File "/usr/lib/python3.5/tarfile.py", line 2040, in extract
        numeric_owner=numeric_owner)
      File "/usr/lib/python3.5/tarfile.py", line 2118, in _extract_member
        self.makelink(tarinfo, targetpath)
      File "/usr/lib/python3.5/tarfile.py", line 2205, in makelink
        self._extract_member(self._find_link_target(tarinfo),
      File "/usr/lib/python3.5/tarfile.py", line 2372, in _find_link_target
        raise KeyError("linkname %r not found" % linkname)
    KeyError: "linkname 'adwaita-icon-theme-3.26.0/Adwaita/cursors/6407b0e94181790501fd1e167b474872' not found"