If an entity with a lazy basic attribute is loaded from the second level cache and the lazy attribute is accessed an exception is thrown. The reason seems to be that the cache entry for the entity attribute yields an instance of org.hibernate.bytecode.enhance.spi.LazyPropertyInitializer.UNFETCHED_PROPERTY which is not handled properly.

https://hibernate.atlassian.net/browse/HHH-11766

This is not a customer issue, but I would consider this a critical bugfix.