Among a whole bundle of NaN's, I get this.
transform.position assign attempt for 'Preview Scene Camera' is not valid. Input position is { NaN, NaN, NaN }.
UnityEditor.AssetPreviewUpdater:CreatePreviewForAsset(Object, Object[], String)
Whatever it is that caused this error is corrupting the sub models as well, I can't get any of them into unity because of these errors.