Rounded corner effect doesn't work well on KDE-Rounded-Corners

[queenbiscuit311]

I've been using this effect for a little while on plasma 6 and while it's great, there's something about it that annoys me. If you use lightlyshaders and set the blur roundness to the same radius as lightlyshaders, everything looks pretty much identical to if I was using the lightlyshaders blur. However, lightlyshaders shadows look really ugly on my theme, so I'm using KDE-Rounded-Corners. But when using that effect, the rounding doesn't quite look right. When using 12px window rounding and 12px blur rounding, it gives this weird beveled edge effect that doesn't quite look right.

KDE-Rounded-Corners

LightlyShaders

Setting blur radius to 14px makes it look better, but in certain situations it is quite obvious that the blur radius is smaller than the window radius.

It's a very minor issue but I thought it would be a good idea to make an issue for it.