You could try a self-lit e-ink (like Kindle Paperwhite) to determine whether it's the light emission. I doubt it. I see the same kind of distraction in myself,

You could try a self-lit e-ink (like Kindle Paperwhite) to determine whether it's the light emission. I doubt it. I see the same kind of distraction in myself, and it's not triggered on any e-ink reader, whether lit or not. So it seems to be related to functionality indeed. Important point is that I've never used a web browser on any reader.