If an embeddable contains an embeddable, and the outer embeddable is instantiated due to hibernate.create_empty_composites.enabled=true, the inner embeddable is not instantiated.
The inner embeddable should be instantiated as well.
I’m working with 5.4.18 and this feature is working. In my case I have a Use class that contains a PersonalData class which in turn contains a FiscalData class. Any field of the PersonalData nor fields from FiscalData are initialized in the db (they are all NULL). But when enabling hibernate.create_empty_composites.enabled=true all the object graph is initialized (including empty embeddables within embeddables, all empty, except for the outer embeddable which has the inner embeddable initialized empty).