You can test this out, go onto the central market and buy 40 Good Feed.

watch it preorder for 3 weeks. (this can be confirmed by a GM checking my game data, i give permission)

but, cancel the preorder (as you can't buy anymore when the preorder is up)

and buy 10 good feed, 10 good feed, 10 good feed, 10 good feed. 

instant access.

Do the same with Black Crystals or anything else. Sometimes the system will put it on Preorder even if it's 1 item. But cancel it, log out log back in and redo the order... and suddenly it's instant.

The central market is borked.

You probably were trying to buy at a price noone was selling. When doing your preorder check under price. It will tell you at what price it's currently being sold and how many