I'm having problem with positioning a QR code on my M5Paper e-ink screen.

Given this very simple piece of Arduino code:

#include <M5EPD.h>

M5EPD_Canvas canvas(&M5.EPD);
const uint16_t Y = 0;

void setup()
{
    M5.begin(false, false, false, false, false);
    M5.EPD.SetRotation(90);
    M5.EPD.Clear(true);

    canvas.createCanvas(540, 960);
    canvas.qrcode("https://www.example.org/", 70, Y, 400);
    canvas.pushCanvas(0, 0, UPDATE_MODE_GC16);
}

void loop()
{
}

When setting Y to 0, the qr code gets placed at the very top of the screen, as expected:

When setting Y to 560 (screen height 960 - size of qr code 400), I would expect the QR code to render at the very bottom of the screen. However, the qr code gets render barely a bit lower than with Y = 0.

Is there something obvious I'm missing?
Any help would be much appreciated.