Your data types are mismatched when you are retrieving the field values.
Also check how you store your enums, default is ORDINAL (numeric value stored in database), but STRING (name of enum stored in database) is also an option. Make sure the Entity in your code and the Model in your database are exactly the same.
I had an enum mismatch. It was set to default (ORDINAL) but the database model was expecting a string VARCHAR2(100char). Solution:
@Enumerated(EnumType.STRING)