Model.createEmptyValue() creates an empty association property that is null

Hi folks, I’m having some troubles in relations in Fusion, I have two entities that are:

class Person {
	@ManyToOne(optional = true)
	@JoinColumn(name = "cidade", referencedColumnName = "codCidade", insertable = false, updatable = false, nullable = true)
	private City city;

class City {
	private Integer id;

When calling from TS view, Model.createEmptyValue(), the city property gives me an empty city besides of a null value, and whe I try to insert to endpoint, gives:

Caused by: org.springframework.dao.InvalidDataAccessApiUsageException: org.hibernate.TransientPropertyValueException: object references an unsaved transient instance - save the transient instance before flushing

Anybody knows what I’m doing wrong?