I'm not a credit card expert, but there's two steps at least, my wife worked for a processor for a while.
1. Auth
2. Charge
The auth is an initial check to verify the charge will go through in the future. On credit cards this may count towards your line of credit for couple of days. Not all auths are converted to charges, or for the same amount. Example:
You go to the gas station. You put your credit card in. Your card is auth'ed for $50 or $75. If you only put in $24.56 of gas then later that day the charge will be made for $24.56. Same thing at restaurants, etc.
You can't charge the credit card until the order ships. So when you press "buy" on a web page your card is authorized for the amount listed. When it ships it's then charged. Now remember auths expire. So before an order would ship, in the prep stage you would expect them to get a new auth before starting to box up your phone since it'e been weeks since they verified you could actually pay for it. NokiaUSA/Brightpoint are running auths every couple of weeks to verify the money you promised to pay them is still available.
I assume this is going to trigger the fraud departments since it looks like some is running a canceled order. For example, you make the order then cancel it. Then some unscrupulous employee could use your card info to buy themselves a phone. Of course, this isn't what's going on.
Amex seems to be very sensitive to this, which is interesting.