Last night I discovered that one of my books was not formatted properly. I fixed the problems on the original text, and re-uploaded that to Nook to replace the old book.
The upload was successful and I received a dialog box saying "the book will be available within 48-72 hours"
I assumed, therefore, that the book would still be on the Nook (coming up in searches) but not available for purchase until the new upload had taken affect.
Today, I checked my sales, and someone bought the book today. It's only been 12 hours - did they get the old and wrongly formatted book, or did they get the new and properly formatted book?