Very strange.
I paid Japanese ¥400 for the pro version. Earlier I had downloaded this app’s free version. They acted in exactly the same way when I searched for Anne of Green Gables; they said “ Downloading/formatting the book for your iPhone… I will dismiss myself when I’m done.” I did the same search for the second time on the pro version. I okayed the same message for the third time and tried downloading the book from the same table listing all the versions of the book, which I had seen all along. The link led me to Google browser. I think this is a total scam.