Tested on Webkit r31878 on Win2k.

Example 1

On the left-hand (first) gradient, a pixel of background is showing through. This goes away at other radius sizes (the right-hand gradient has 11 instead of 10 as the first radius).

Is the light green colour meant to continue drawing outside the boundary of the gradient? Example 2 shows what happens if to(rgba(1,159,98,0)) is changed to color-stop(98%, rgba(1,159,98,0)). Note that using 99% still draws green, but a lighter shade.

Example 2

This is what I expected when using to().