Nothing rendered when calling Draw.RectangleBorder in succession

I'm calling Draw.RectangleBorder twice in a row, and when I do so, nothing is rendered. If either is changed to Draw.Rectangle, then both shapes are rendered. Am I missing something obvious, or is this a bug? My full code is below.

    public override void DrawShapes(Camera cam)
    {
        using (Draw.Command(cam))
        {
            // set static parameter to draw in the local space of this object
            Draw.Matrix = transform.localToWorldMatrix;

            Draw.RectangleBorder(new Vector3(selectionPosition.x, selectionPosition.y), new Rect(Vector2.zero, new Vector2(selectionSize, selectionSize)), 2f);
            Draw.RectangleBorder(new Vector3(borderPosition.x, borderPosition.y), new Rect(Vector2.zero, new Vector2(ChunkData.SIZE, ChunkData.SIZE)), 2f);
            
        }
    }