The Nexus 6 is having a rough start on AT&T. The carrier is shipping back its unsold inventory to Motorola in order to fix a major software bug, according to various reports. The software issue leads to the screen turning black on some units and can also prevent the phone from connecting to the AT&T network. At this point, it is only the initial batch of Nexus 6 units sent to AT&T that has been recalled. These technical issues may or may not have to do with AT&T's modifications to the phone, but it seems like an awfully big coincidence that other carriers, who haven't changed the Nexus 6, aren't experiencing the same issue.