The Nexus 6 is pretty difficult to come by. Google only releases stock in stages, and carriers are just now getting the device. On top of all that, some can’t even figure out pricing, which recently caused last-place Sprint to issue contract credits for over-charging customers. Now, AT&T has run dead into the Nexus wall, and have chosen to return all Nexus 6 inventory to Motorola. The reason? Software! Motorola evidently shipped the wrong software to AT&T, though it’s not clear what the issue was.