Some of them had their codes altered, that's all. VZW cannot magically alter the unlock code on a phone that doesn't have internet access. Now, if you bought the D2G and instead of unlocking it first decided to set up WiFi, you obviously can get those codes changed accidentally if it's really done OTA.
I somehow doubt it, though, and I think the codes are just wrong. I.e. the phone had some other code flashed into it at the factory, not the one that is in the database.
There's no reliable way to confirm that VZW changes the codes OTA, is there?