It is nothing to cheer about but seems the “supply constraint of some components” was really an issue with Lumia 920’s volume. CEO Elop has confirmed in a post “press-release” conference call that Nokia was hit by short supplies of some of its new phones, including the Lumia 920. They specially mentioned AT&T having “significant supply issues” with the Lumia 920.

Elop also said, the firm would have sold more Lumia handsets if it could have met the demand. The shortage was not only cause by cautious ordering, he added, but there had also been a lack of adequate supplies of some components. We are working with suppliers and operators to work through the situation today.

Elop also said he is pleased with the initial response to the new Lumia devices and  Nokia plans to begin ramping up on deliveries of the smartphones and entering  new markets.

Source  Source 2