Hello joab!! 

Can you recreate that situation and share an OML?

You need to inspect and see in which position is that "1/2" if it's outside where you have the legend and the chart of course the border will not include the "1/2". If you have a position absolute, I think it will be outside of that container where have the legend and the chart are. If has a position absolute, you need to give a space based on the size that 1/2 it's occupying. That way maybe it will be inside. But this is just a supposition, I needed to put my hands on it to see it clearly.

Marcio