Hallo!
Have a similar problem on my 350. After using it 2 weeks a spot had become visible. If you take a 10x magnifier it looks like a bubble or a tiny part of an transparent plastic between the front plastic layer of the screen and the underlying functional e-ink layer. It is clearly visible, that this 'thing' has some height.
I just don’t understand why it was not visible at the beginning.
I called Sony ant they gave me the contact address of the repair center. I'l send them the reader inbetween the next view days.
A
