Sean, as you are aware, opened boxes of film have the humidity seal broken. The humidity, when you place it back in the freezer is then that of the room it was in before it was put back in the freezer. Therefore, as it cools, humidity goes up and moisture condenses and can cause sticking.
If I have to place opened packs of film back into storage, I prefer using the refrigerator rather than the freezer, as the chance of this happening is lower.
Film is packed at Kodak at 70deg F/50% RH IIRC. Even under these conditions, low temperatures can cause a tiny bit of condensation if chilled low enough. Any lower packaging humidity would cause problems with static electricity discharge during the operation.
So far, I have been lucky even though I store my film at well below zero F in our freezer.
Sorry to hear you lost a sheet of 8x10. That stuff is expensive.
PE