Mini Kobo Mini Bookmark question

Hi all

I have just purchased a Kobo mini for my wife, i have one niggling problem with it that i cant seem to suss out.

Basically when she reads a book and turns it off it does not go back to where she was when she switches it back on, it seems to go about 2 pages back from where she left it.

We have tried going back to the home page and then turning it off and also just turning it off whilst reading and still the same thing. If she is on page 34 for example it will go back to page 32 or 33 when she next goes to read.

Any ideas?

Thanks all