During adding points to area chart, fill color becomes transparent

[stanleyxu2005]

I have a chart type=area with two data series stacked=0, stacking='normal', animation=false. Series 1 has fill color blue, series 2 has fill color green. Everything is just fine, but when I add new data points to both series (x-axis is datetime), the fill area will become shortly transparent (see pic left), until the animation is finished (see pic right).

Have I missed some property to make this right, or is it a known bug?

[pawelfus]

It's duplicate of #1841