Error is generated when loading (via SerializationUtility.DeserializeValue<T>(bytes, format)) a serialized basic class (via SerializationUtility.SerializeValue) that contains dictionaries. Replacing dictionaries with lists using the values from the dictionaries eliminates errors. I tried both enum and strings keys with the dictionarues with the same results.
Data outside of these dictionaries is loaded.
JSON and binary data behave the same, though the error is logged only when using binary serialization. This made tracking this down... harder.
Unity - 2017.1.1f1 Odin - 188.8.131.52