Steps to reproduce
- Login as admin.
- Create a course and add a book with a chapter.
- Go to the main course page.
- Turn editing mode off.
- Access to the book.
- Check the URL is something like "mod/book/view.php?id=xxx".
- Click the Turn editing on button.
The URL preserves all the parameters (so it keeps being "mod/book/view.php?id=xxx").
The URL is set to mod/book/view.php
Although I don't think this is causing some issue right now, I've faced it might fail once