The stack overflows when the existing path is being removed from the segment with -= operation

When rendering semi transparent figures, we remove overdrawn lines in code similar to the example attached. The code stack overflows with the following call stack:
.....
  Qt5Guid.dll!QKdPointTree::build(int begin, int end, int depth) Line 691 C++
  Qt5Guid.dll!QKdPointTree::build(int begin, int end, int depth) Line 691 C++
  Qt5Guid.dll!QKdPointTree::build(int begin, int end, int depth) Line 691 C++
  Qt5Guid.dll!QKdPointTree::build(int begin, int end, int depth) Line 691 C++
  Qt5Guid.dll!QKdPointTree::QKdPointTree(const QPathSegments & segments) Line 623 C++
  Qt5Guid.dll!QPathSegments::mergePoints() Line 763 C++
  Qt5Guid.dll!QWingedEdge::intersectAndAdd() Line 798 C++
  Qt5Guid.dll!QWingedEdge::QWingedEdge(const QPainterPath & subject, const QPainterPath & clip) Line 868 C++
  Qt5Guid.dll!QPathClipper::clip(QPathClipper::Operation operation) Line 1613 C++
  Qt5Guid.dll!QPainterPath::subtracted(const QPainterPath & p) Line 3344 C++
  Qt5Guid.dll!QPainterPath::operator-(const QPainterPath & other) Line 2358 C++
  Qt5Guid.dll!QPainterPath::operator-=(const QPainterPath & other) Line 2408 C++
  tabvizrender.dll!rendering::QtLineMarkElement::DrawLineEdge(double x1, double y1, double width1, trt::core::TrtColor color1, double x2, double y2, double width2, trt::core::TrtColor color2, double strokewidth, QtDrawContext & painterContext, QPainterPath & linePath, bool flattenLayers, int left, int current, int right, bool isStepLineJoin) Line 14644 C++
 

Source in DrawLineEdge:

QPainterPath lineSegment;
lineSegment.addPolygon(QPolygonF(points));
int existingCount = existingPath.elementCount();
lineSegment -= existingPath;

To repo with the attached files:

QDataStream existingPathStream;
 QDataStream lineSegmentStream;
// Open the attached files into existingPathStream and lineSegmentStream
QPainterPath lineSegment;
QPainterPath existingPath;
existingPathStream >> existingPath;
lineSegmentStream >> lineSegment;
lineSegment -= existingPath;