Dolfin-convert crashes with KeyError

[jakub.mateusz.kowalski]

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fenics@01f23cc3889e:~/shared$ dolfin-convert eighth_of_sphere.msh eighth_of_sphere.xml
Converting from Gmsh format (.msh, .gmsh) to DOLFIN XML format
Expecting 268559 vertices
Found all vertices
Expecting 1433110 cells
Found all cells
Traceback (most recent call last):
  File "/usr/local/bin/dolfin-convert", line 132, in <module>
    main(sys.argv[1:])
  File "/usr/local/bin/dolfin-convert", line 79, in main
    meshconvert.convert2xml(ifilename, ofilename, iformat=iformat)
  File "/usr/local/lib/python3.6/dist-packages/dolfin_utils/meshconvert/meshconvert.py", line 1301, in convert2xml
    convert(ifilename, XmlHandler(ofilename), iformat=iformat)
  File "/usr/local/lib/python3.6/dist-packages/dolfin_utils/meshconvert/meshconvert.py", line 1322, in convert
    gmsh2xml(ifilename, handler)
  File "/usr/local/lib/python3.6/dist-packages/dolfin_utils/meshconvert/meshconvert.py", line 494, in gmsh2xml
    index = nodes_as_facets[tuple(nodes)]
KeyError: (12405, 17846, 26376)

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[jakub.mateusz.kowalski]

the issue seems to be strictly related to the mesh. There is a physical surface composed of surfaces which are not included in surface loops limiting physical volumes. With the physical surface removed dolfin-convert works as expected.