You probably need to kick the sidemenu of the Book window, and manually ask to update the numbering of all pages, in order to let InDesign reshuffle them properly.
As you can see in my (Dutch) example, it's also not correct. I moved the three page document between two one-pages, messed a bit with moving pages and Undo and all, and then the page numbering went astray. Just update the numbering.
Of course the numbering options of the Book itself need to be set to continue automatically. And check if there are any spreads in documents having [brackets] around their numbers in the Pages panel, to always keep them together (then they're not allowed to be shuffled automatically). They could block the automated sequence of pages forming proper spreads. (I don't see any so far.)