Need help with Nexus 6 XT1103 OTA

I bought two Nexus 6's from Amazon (USA) because they are supper good deals right now at 9. I picked up two identical devices, 32GB Cloud White - they are US models XT1103, they were sealed the same way as my first Nexus 6 from Google Play Store a year ago. But, when I powered them one, one updated from 5.1 to 5.1.1 and after that right to 6.0 while the other one will not, no matter what get any OTA. I tried clearing device cashe memory, I tried clicking "update device", I tried hard reset, I tried clearing Google Framework Services and force stopping it. Nothing works. I don't want to flash manually, I want the OTA. Can someone tell me why this is happening and what I can do to fix it? Thank you