There is no white line on mine.
Btw, Monday products do not exist 😉

In dark mode with bright illumination, a narrow line is also visible on my right. I have just discovered this, but it is not important for me because I almost only read without illumination in standard mode.

So when I look straight in from above, I don't have a white border. But the way I hold the device again, I can see one on the right. Theoretically it is visible everywhere if I hold it at an angle. Hope this helps.