Maybe the paddles (for the crossing) are back-ordered.
Well, the books are printed in the good old USA (at least the English version) so those book get shipped from Indiana (where one of the
Courier facilities are located). I've actually visited the printer for a press proofing the first time I did a Real World Camera Raw update (for Photoshop CS3).
Since then my books have been printed without my attending the press proof because, well, I've gotten really good at preparing the images in my books for CMYK repro...
(hint, I use PhotoKit Sharpening 2 for halftone output for all the figures in the book with screenshot upsampled 200% using Nearest Neighbor then doing a dual separation with normal GCR and a Max K sep). Kinda geeky...sorry!
So, if the books started in Indiana (where my books are printed), they would be trucked to the coast, then loaded into a container, then a container ship and shipped to Europe...so it takes a while to get overseas...