Cannot draw corners round enough

Question

The rounded Rectangles created with the same height and corner radius, but it seems that the x radius became longer and longer as the rectangle became wider.

The orners are not curves as I expected (blue stroke one).

Did I miss something on setting the canvas?

    canvas.save()
    canvas.translate(body.position.x * mDpm, body.position.y * mDpm)
    canvas.scale(bw * mDpm, bh * mDpm)
    canvas.rotate(getScreenRotate(body.angle))
    mPaint.style = Paint.Style.FILL
    mPaint.color = mColorFill
    val rect = RectF(-1f, -1f, 1f, 1f)
    canvas.drawRoundRect(rect, bh*2, bh*2, mPaint)
    canvas.restore()