The Lumia 900 (both black and cyan) has gone out of stock according to the product listing at the online AT&T store. Nokia has recently confirmed a memory management issue with the Lumia 900 running on AT&T that would kill the data connection, rendering the Windows Phone almost useless for owners while on the go.
Since the announcement was made Nokia has offered $100 on the bill of affected AT&T and Rogers customers and has also begun rolling out the firmware fix for the connectivity bug days early. There have been reports that the U.S. carrier has been pulling handsets from shelves in favour of models with the update already installed. We haven't heard anything official but this could explain why the handset is temporarily "out of stock".
The amount of Lumia 900s left for shipping could have been snatched up by a relatively high number of orders. Then again, AT&T has publicly stated that the Lumia 900 has been selling beyond expectations (even the cyan case was listed as out of stock). We'll not know the exact numbers, but for now it'll be an anxious wait for the second batch of handsets to be made available for orders to run through.
Let us know if you've been able to find any Lumia 900 devices locally or if you've seen that the Windows Phones were pulled due to the update issues.
Source: AT&T; thanks everyone who tipped us!