The Flipbook pages are loading too slowly, even after optimizing the pdf for the web. Its like the pages are being lazy loaded and only loaded when you click the arrow to view.
Furthermore it seems like the last 2 pages of the catalog are loaded even before page 2-3 which makes no sense. This also happens with the demo on your site.
Bellow are my settings and the URL to the catalog, can you please check it out. Thank you!
Here is the same pdf but not web optimized loading much faster.