border radius in android

I'm trying to create a circle and have a view with a width and height set to double a border radius:

Example:

"#estimateHolder": {
    width: 210,
    height: 210,
    borderRadius: 105,
    borderColor: "black",
    borderWidth: 3
}

On iPhone this draws a circle with a diameter of 210. On android it draws a rounded rect. The funny thing is that if I say the border radius is 210 .. it will draw a circle on android.

Is this a framework bug?