Internally we have an annotation processor that generates some entities from another meta model. This is something like a mix with concrete entities and generated entities.
The problem is that when I have a concrete entity, the Hibernate Metamodel Generator generates the JPA metamodel in a first compilation phase. Our processor generates our entities and the Hibernate Metamodel Generator is called again to generate metamodel for the generated entities and once it has the same context it tries to generated again the same entity from the first phase, resulting in a error:
So, I've sent a pull request to keep the already generated classes inside the Context and check it from the Context.