In the apple books app on iphone, purchased books show up as unpurchased

For certain books that I purchased, the books show up as unpurchased in my collections. However if I view the book in the store, the books show up as purchased with the option to download the book. Has anyone else seen this? I believe it is a bug within the app. This might occur because when I originally add a book to a collection before I purchase it, and then purchase it later on, the app doesn't properly update the information for that particular book.