Line segments in geom_density2df() do not get interpolated when used with coord_polar()

[IKupriyanov-HORIS]

Code snippet:

from lets_plot import *
LetsPlot.setup_html()
p = ggplot() + geom_density2df(aes(x=[0, 1], y=[0, 1], fill='..level..'), bins=6, show_legend=False) 

gggrid([
    p,
    p + coord_polar()
])

Expected:
The plot should have form of a circle.

Actual:
The plot has a jagged edge, the segments near the edge of the plot have not been interpolated.