Issue with ui.viz.pie

I am still running on the older version of viz chart and in the pie chart I notice some unexpected rendering problem for the legend. At first I thought it was only on my local system but after which I tweak the testsuite (online version) it seems that the issue is random and real.

Apparently it seems that the pie chart legend is unable to render properly strings that are just 2 characters or what I thought as so.

Will be nice if someone has a solution to it. Just a note that would not be able to change to the latest charting control for the time being.