LineWidth bug when using patch

I am using patch to draw a circle using X and Y coordinates. The radius varies slightly so I computed and normalized the radius data and am using it in combination with a colormap to highlight the min and max values of the radius around the border.

The problem occurs when I attempt to increase the LineWidth to make the plot easier to see but am finding that it doesn't accept modifications to the property as long as EdgeColor is set to 'interp'. If I remove the EdgeColor property, it will accept the LineWidth property and draw a thick black line.

The marker properties work fine, it's just the LineWidth. Also, if I set LineStyle to 'none', the line successfully disappears.

patch(xData,yData,rcolor,'FaceColor','none','EdgeColor','interp','LineWidth',5)

Is this a bug, or am I missing something else. Currently using version r2013b.