QLineSeries.clear() does not remove all lines from the plot in that series

The QLineSeries.clear() method appears to correctly delete points in a QLineSeries, but only gets rid of some lines made in the plot from those points, not all of them.

Steps to Reproduce:

I've attached a script where a simple LineSeries plot is made on 2 ValueAxis objects.  There is a button attached to a slot that will clear the points in the QLineSeries object.  After this button is pressed, the points on the QLineSeries are removed, but there is still a line that exists on the plot despite no points existing.  Trying to call QPolarChart.update() or the QChartView.repaint() doesn't seem to have any effect.

Expected Results:

All points and lines should be removed.

Actual Results:

There are some artifacts of the previous lines that remain even after the points are removed.  See attached picture.

Extra Information:

We've tested this on both Mac and Windows and seen the same results.