IPhone activations at AT&T (T) grew by just 3% in the second quarter this year, and many industry watchers pointed to the flood of next-generation iPhone rumors as a likely culprit for the slowed growth. BGR has exclusively learned that this is not entirely the case, however, and the stalled iPhone sales at the nation’s No.2 wireless carrier may in fact be by design.

Updated with official statement from AT&T after the last paragraph.

Regional retail sales managers at AT&T have been instructing store managers to pump the brakes on Apple’s iPhone. Instructions handed down from corporate state that customers seeking smartphones at AT&T retail stores should be steered away from Apple’s (AAPL) iPhone and towards Android phones or Windows Phone handsets like the Nokia Lumia 900 instead. BGR has confirmed the directive with three independent sources.

Even when customers come into stores specifically looking for the iPhone 4S or iPhone 4, staffers have been instructed to make an effort to show people Android and Windows Phone devices as well, so they can “make an informed decision.” In addition, AT&T retail staff in at least some locations are no longer permitted to obtain iPhones as their company-owned devices, and must instead choose an Android smartphone or a Windows Phone.

AT&T did not immediately comment.

One source told BGR that Apple’s iPhone used to make up as much as 80% of smartphone sales at stores in his area, but that figure has dropped dramatically to between 50% and 60% since regional managers instructed stores to actively push other smartphones in place of the iPhone.

Apple handsets still accounted for 72% of all smartphones activated by AT&T during the second quarter this year.

UPDATE: AT&T contacted BGR via email and supplied the following statement:

The idea that we would steer any customer away from a particular device couldn’t be more farfetched. Our reps do what it takes to align customer needs with the best device for them. iPhone remains one of our most popular devices, which doesn’t happen by steering people away from it. Our reps are encouraged to try all devices so they are more knowledgeable on our industry-leading smartphone lineup.