CompletableFuture.isDone blocks CrudRepository.save(); - spring

Question

I'm trying to store an entity in my database in an async method by returning a CompletableFuture<>. The code works fine as long as I do not check the state of the future (e.g isComplete() or .get()).
CompletableFuture<Product> working = serviceTest.test("working");
The above example works, the product is stored in the database.
#Async
public CompletableFuture<Product> test(String name)
{
Product p = new Product();
p.setId(new Random().nextInt(500000));
p.setName(name);
logger.info("Saving "+ name);
p = productRepository.save(p);
logger.info("finished " + name);
return CompletableFuture.completedFuture(p);
}
However, as soon as I change the code to for example
CompletableFuture<Product> notWorking = serviceTest.test("notWorking");
notWorking.get();
The entity is not saved and the code freezes at 'productRepository.save(p);'.
What is the correct way to save entities in an async method? Note that this is a simplified example and in the real scenario the test function is a long running operation to fetch a list of products from an external server.
The not explainable issue for me is that a simple method to get the state of the future blocks the saving of my entity.
I extracted a thread dump when the deadlock occurs. This is the relevant part
"MigrationTask-1" #19 prio=5 os_prio=0 tid=0x00007fbdd4bcd800 nid=0x16ea waiting for monitor entry [0x00007fbda9274000]
java.lang.Thread.State: BLOCKED (on object monitor)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:187)
- waiting to lock <0x00000000850ab208> (a java.util.concurrent.ConcurrentHashMap)
at org.springframework.beans.factory.support.AbstractBeanFactory.isTypeMatch(AbstractBeanFactory.java:486)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doGetBeanNamesForType(DefaultListableBeanFactory.java:432)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeanNamesForType(DefaultListableBeanFactory.java:403)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeanNamesForType(DefaultListableBeanFactory.java:389)
at org.springframework.beans.factory.BeanFactoryUtils.beanNamesForTypeIncludingAncestors(BeanFactoryUtils.java:177)
at org.springframework.beans.factory.annotation.BeanFactoryAnnotationUtils.qualifiedBeanOfType(BeanFactoryAnnotationUtils.java:89)
at org.springframework.beans.factory.annotation.BeanFactoryAnnotationUtils.qualifiedBeanOfType(BeanFactoryAnnotationUtils.java:66)
at org.springframework.transaction.interceptor.TransactionAspectSupport.determineQualifiedTransactionManager(TransactionAspectSupport.java:382)
at org.springframework.transaction.interceptor.TransactionAspectSupport.determineTransactionManager(TransactionAspectSupport.java:363)
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:272)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:136)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodInterceptor.invoke(CrudMethodMetadataPostProcessor.java:133)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.data.repository.core.support.SurroundingTransactionDetectorMethodInterceptor.invoke(SurroundingTransactionDetectorMethodInterceptor.java:57)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:213)
at com.sun.proxy.$Proxy96.save(Unknown Source)