Perspective tootips - zero == NaN?

data = {'x': [1, 2, 3], 'y': [0, 2, 3]}
pn.pane.Perspective(data, width=1000, group_by = ['x'], columns = ['y'], plugin = "d3_y_line")

The tooltip/hovertool shows NaN when the column data is 0. I have tried changing the aggregate functions to see if that has any effect and the few that I tried didn’t change the tooltip. I suspect this is a bug?