Why does my ePub fixed layout file not look right in ADE?

I have just created an ePub 3 fixed layout file in InDesign CC (2015). When I open this in iBooks, it looks great but in ADE, my 32 page picturebook appears as over 250 pages and each single page is spread over about three. I'm not sure why this has happened - is there a simple fix?

Many thanks,

Caroline