Well, I think I found the issue. The item numbers on the carts and on the case are different, which is something I quite honestly never realized before since I always register the number on the cart, not the one on the case. The carts in all of Europe probably all bear the same number (LNA-CTR-BD7P-EUR), my case has the number TSA-CTR-BD7P-GER (it's quite obviously the German release - I usually avoid getting these since I don't like the huge-ass USK sticker on the front but this one was a present). I can't verify this for sure, though.
But if that's the case, does it really make sense to make separate entries for ALL of the various European releases? There's probably no actual difference between them, since this particular game is available in English only.