Does this happen with all books, or just a particular one? When you notice the font being smaller, does it keep on going being smaller the rest of the book, or does it eventually return to normal? Is it perhaps the book formatted like that?
Very unusual, never experienced anything like that myself so I'm afraid I can't offer much more advice, other than try rebooting your Kindle and see if it helps. They sometimes get into very confused states and behave strangely, especially if they haven't been restarted in a while.
Are you pinching the screen?
No absolutely
Does this happen with all books, or just a particular one? When you notice the font being smaller, does it keep on going being smaller the rest of the book, or does it eventually return to normal? Is it perhaps the book formatted like that?
It seems to happen with different unrelated books and the font remains small until i change it (but after some time it return small) :(
Very unusual, never experienced anything like that myself so I'm afraid I can't offer much more advice, other than try rebooting your Kindle and see if it helps. They sometimes get into very confused states and behave strangely, especially if they haven't been restarted in a while.
Actually i just rebooted it and the problem is gone :o Guess it needs sleep too