"Not a managed type" error after spring/hibernate update

After updating spring and hibernate we started getting the following error in some of our tests.

Spring: 6.1.3 Spring-boot: 3.2.2 Hibernate: 6.3.1.Final

Caused by: java.lang.IllegalArgumentException: Not a managed type: class a.b.c.MyClass
    at org.hibernate.metamodel.model.domain.internal.JpaMetamodelImpl.managedType(JpaMetamodelImpl.java:193)
    at org.hibernate.metamodel.model.domain.internal.MappingMetamodelImpl.managedType(MappingMetamodelImpl.java:463)
    at org.hibernate.metamodel.model.domain.internal.MappingMetamodelImpl.managedType(MappingMetamodelImpl.java:97)
    at org.springframework.data.jpa.repository.support.JpaMetamodelEntityInformation.<init>(JpaMetamodelEntityInformation.java:82)
    at org.springframework.data.jpa.repository.support.JpaEntityInformationSupport.getEntityInformation(JpaEntityInformationSupport.java:69)
    at org.springframework.data.jpa.repository.support.JpaRepositoryFactory.getEntityInformation(JpaRepositoryFactory.java:246)
    at org.springframework.data.jpa.repository.support.JpaRepositoryFactory.getTargetRepository(JpaRepositoryFactory.java:211)
    at org.springframework.data.jpa.repository.support.JpaRepositoryFactory.getTargetRepository(JpaRepositoryFactory.java:194)
    at org.springframework.data.jpa.repository.support.JpaRepositoryFactory.getTargetRepository(JpaRepositoryFactory.java:1)
    at org.springframework.data.repository.core.support.RepositoryFactorySupport.getRepository(RepositoryFactorySupport.java:317)
    at org.springframework.data.repository.core.support.RepositoryFactoryBeanSupport.lambda$afterPropertiesSet$5(RepositoryFactoryBeanSupport.java:279)
    at org.springframework.data.util.Lazy.getNullable(Lazy.java:135)
    at org.springframework.data.util.Lazy.get(Lazy.java:113)
    at org.springframework.data.repository.core.support.RepositoryFactoryBeanSupport.afterPropertiesSet(RepositoryFactoryBeanSupport.java:285)
    at org.springframework.data.jpa.repository.support.JpaRepositoryFactoryBean.afterPropertiesSet(JpaRepositoryFactoryBean.java:132)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1820)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1769)

After stepping through the hibernate code I believe it is caused by this change Re-add AvailableSettings.JPA_METAMODEL_GENERATION and re-enable metam… · hibernate/hibernate-orm@1184a59 · GitHub Our entity classes implement java.util.Map so they get excluded from entityTypes in the registerEntityType method.

Is this no longer allowed or is there some configuration we need to do?

This could be a bug. Please try to create a reproducer with our test case template and if you are able to reproduce the issue, create a bug ticket in our issue tracker and attach that reproducer.