Yep, davidfor fixed the bug a couple of years ago - but now I'm trying to remember the symptoms and the cure!!
From memory the symptoms were that even when you dog ear bookmarked the page and then either turned the unit off directly, or went back to the main screen and turned the device off, when you came into the book again it was at least one or more pages back from the dog ear page.
The fix was something to do with the margins. So from memory we had to keep the margin slider at the far left, in other words the 'off' position.
And I think it was as simple as the margin slider. David I'm testing your memory on this one .....