anchor.diff:          } else if (unique) {
             // keep sum within float32 precision
             _sum = doubleToSingle(_sum + weight);
  +          _threshold += 2e-7;
           }
         } else if (joint != 0) {
           context.addIssue(DataError.accessorJointsUsedZeroWeight,
  
positive.code:     }
  
      if (4 == ++_componentIndex) {
        // Threshold depends on the number of used joints
        //   step ~= 1/255
        //   1..2 elements - 0 * step
        //   3..4 elements - 1 * step
        //   5..6 elements - 2 * step
        //   7..8 elements - 3 * step
  
        final threshold =
            unitSumThresholdStep * (((_currentIndices.length + 1) >> 1) - 1);
        if ((_sum - 1.0).abs() > threshold) {
          for (var i = 0; i < jointsIterators.length; i++) {
            context.addIssue(DataError.accessorWeightsNonNormalized,
                name: '$path/${WEIGHTS_}_$i', args: [_index - 3, _index, _sum]);
  
negative.code:   bool _done = false;
  
    double _sum = 0;
    double _threshold = 0;
    final Set<int> _currentIndices = <int>{};
  
    InfluencesChecker(this.path,
  