Grafana Bar Chart "Stacking Percent"

Hello all,

I have a question regarding Bar Chart and “Stacking Percent” option.
I have the following data visualized with a bar chart, d1 and d2 being two different measurements;

If I use the “Stacking Normal” option everything is fine and -as I would expect- d1 and d2 are shown in the legend:

If I use the “Stacking Percent” for some reason, only d1 is shown twice in the legend:

I’d like to see d1 and d2 in the legend like with the “Stacking Normal” option.
Can anyone help please? Thank you!