[Kriemfield]

I did some more tests, by selecting the cover, closing, reopening, selecting another page, closing again and reopening, I managed to set it to the cover again, but it is quite weird. I turn pages by scrolling with the mouse or clicking on the contents sidebar.
Now, if I close at another page, it returns to the cover when I reopen the ebook. It looks like it gets stuck on a page at some point.

Edit: The "previous page" and "next page" buttons don't seem to work.