QChart addSeries() function generates mysterious point (Bug?)

[LordHoratio]

I have a shared pointer named resultsPtr that points to a vector of synthesisResults (custom class). A synthesis result has a latency vale and area value that I'm trying to display on a scatter chart. I have a QchartView I created from the editor and here is the pertinent source code (I can include the whole thing if necessary):

ui->resultScatterChart->chart()->removeAllSeries();
QScatterSeries *resultScatterSeries = new QScatterSeries();

resultScatterSeries->setMarkerShape(QScatterSeries::MarkerShapeRectangle);
resultScatterSeries->setMarkerSize(10.0);
resultScatterSeries->setColor(QColor(230, 200, 0));

for (unsigned int i = 0; i < resultsPtr->size(); i++)
{
    resultScatterSeries->append(resultsPtr->at(i).area, resultsPtr->at(i).latency);
}

QChart *theChart = ui->resultScatterChart->chart();
theChart->addSeries(resultScatterSeries);
theChart->createDefaultAxes();

The result of running this code with a single result in the vector is thus:

Here's what happens when I comment out the call to setDefaultAxes():

Note the extra dot at the top of chart, outside the grid. Interestingly, even if I comment out the call to append inside the loop, that point will still appear in that exact position even without the grid.

Here is all I could establish while trying to debug:

1. The chart only contains one series by the end of the function
2. That series only has 1 point; the one that displays in the center of the chart

By all accounts, it seems that point there shouldn't even exist. How do I get rid of it?