`WyckoffPositions` is not consistent with international tables for crystallography

Observed behaviour

Cryst returns five Wyckoff positions for crystallographic space group No.100(P4bm):

gap> S := SpaceGroupIT(3, 100);
SpaceGroupOnRightIT(3,100,'1')
gap> wyckoffs := WyckoffPositions(S);
[ < Wyckoff position, point group 2, translation := [ 0, 0, 0 ], 
    basis := [ [ 0, 0, 1 ] ] >
    , < Wyckoff position, point group 2, translation := [ 0, 1/2, 0 ], 
    basis := [ [ 0, 0, 1 ] ] >
    , < Wyckoff position, point group 3, translation := [ 1/2, 0, 0 ], 
    basis := [ [ 1, 1, 0 ], [ 0, 0, 1 ] ] >
    , < Wyckoff position, point group 4, translation := [ 1/2, 0, 0 ], 
    basis := [ [ 1, -1, 0 ], [ 0, 0, 1 ] ] >
    , < Wyckoff position, point group 1, translation := [ 0, 0, 0 ], 
    basis := [ [ 1, 0, 0 ], [ 0, 1, 0 ], [ 0, 0, 1 ] ] >
     ]
gap> WyckoffOrbit(wyckoffs[3]);
[ < Wyckoff position, point group 3, translation := [ 1/2, 0, 0 ], 
    basis := [ [ 1, 1, 0 ], [ 0, 0, 1 ] ] >
    , < Wyckoff position, point group 3, translation := [ 1/2, 0, 0 ], 
    basis := [ [ -1, -1, 0 ], [ 0, 0, 1 ] ] >
    , < Wyckoff position, point group 3, translation := [ 0, 1/2, 0 ], 
    basis := [ [ -1, 1, 0 ], [ 0, 0, 1 ] ] >
    , < Wyckoff position, point group 3, translation := [ 0, 1/2, 0 ], 
    basis := [ [ 1, -1, 0 ], [ 0, 0, 1 ] ] >
     ]
gap> WyckoffOrbit(wyckoffs[4]);
[ < Wyckoff position, point group 4, translation := [ 1/2, 0, 0 ], 
    basis := [ [ 1, -1, 0 ], [ 0, 0, 1 ] ] >
    , < Wyckoff position, point group 4, translation := [ 1/2, 0, 0 ], 
    basis := [ [ -1, 1, 0 ], [ 0, 0, 1 ] ] >
    , < Wyckoff position, point group 4, translation := [ 0, 1/2, 0 ], 
    basis := [ [ 1, 1, 0 ], [ 0, 0, 1 ] ] >
    , < Wyckoff position, point group 4, translation := [ 0, 1/2, 0 ], 
    basis := [ [ -1, -1, 0 ], [ 0, 0, 1 ] ] >
     ]

Expected behaviour

The number of Wyckoff positions is inconsistent with International Tables for Crystallography volume A(ITA). In ITA, there are four Wyckoff positions for this space group type. https://it.iucr.org/Ac/ch2o3v0001/sgtable2o3o100/

In the above example, I find wyckoffs[3] and wyckoffs[4] are the same Wyckoff position(Wyckoff letter 4c), since WyckoffOrbit(wyckoffs[3])[1] and WyckoffOrbit(wyckoffs[4])[3] are actually the same Affine space up to translation.

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┌───────┐ GAP 4.10.0 of 01-Nov-2018 │ GAP │ https://www.gap-system.org └───────┘ Architecture: x86_64-pc-linux-gnu-default64 Configuration: gmp 6.1.2, readline Loading the library and packages ... Packages: AClib 1.3.1, Alnuth 3.1.0, AtlasRep 1.5.1, AutoDoc 2018.09.20, AutPGrp 1.10, CRISP 1.4.4, Cryst 4.1.18, CrystCat 1.1.8, CTblLib 1.2.2, FactInt 1.6.2, FGA 1.4.0, GAPDoc 1.6.2, IRREDSOL 1.4, LAGUNA 3.9.0, Polenta 1.3.8, Polycyclic 2.14, PrimGrp 3.3.2, RadiRoot 2.8, ResClasses 4.7.1, SmallGrp 1.3, Sophus 1.24, SpinSym 1.5, TomLib 1.2.7, TransGrp 2.0.4, utils 0.59 Try '??help' for help. See also '?copyright', '?cite' and '?authors'

gap-packages / cryst