Fixed-layout ePub, image links going to the wrong pages?

Hey there! I'm looking at a fixed-layout EPUB, and it has a little navigation bar at the top with icons that are images linked to different chapters. This works fine in iBooks and sort of okay in ADE on a Mac (v4.098)—when you jump somewhere via a link, the scroll bar at the bottom of the screen never updates, so when you advance a page you're back to a page past where you clicked the link from. I know that's a tongue-twister, sorry.

More importantly, in ADE on a PC, the link buttons just go to the entirely wrong chapters. They go somewhere, just not to the right places. But they do go to the right places in ADE on a Mac and in iBooks, so it's not just that the links are pointed to the wrong place.

Is this normal glitchy behavior that's down to ADE's testy relationship with FXL, or does this sound like something that can be fixed, either in the book's code itself or somehow in my settings? Thank you for any info you can maybe provide!