Users who activate Apple’s own SIM card to use an AT&T data plan with the Wi-Fi + Cellular models of iPad Air 2 or iPad mini 3 are finding the SIM will lock itself to AT&T, and can no longer be used by another network. Though it appeared the SIM card would be interchangeable between AT&T, Sprint, and T-Mobile — though not Verizon — it’s not the case with AT&T. The issue was confirmed by Re/code through AT&T spokesman…
