Spring boot - Mockito being ignored in @Async function

Question

I am writing tests for some async methods where I want to mock that an exception is thrown. These methods were synchronous and the tests we working fine until now that I made them async and for some reasy the mocked exception isn't being thrown.

My test:

@MockBean
private RestTemplate rest

@Autowired
private ServiceImpl mockedService;

@Test(expected = MyException.class)
public void test1() {
    when(rest.exchange(Mockito.anyString(), 
            Mockito.any(HttpMethod.class), 
            Mockito.any(HttpEntity.class), 
            Mockito.eq(ParameterizedTypeReference.class)))
    .thenThrow(new MyException());

    this.mockedService.method();
}

The method I am trying to test:

@Autowired
private RestTemplate rest;

@Override   
@Async
public void method() {

   ...      

  try {
    rest.exchange(builder.toUriString(), HttpMethod.GET, entity, new ParameterizedTypeReference<MyObject>() {});
    responseEntity.getBody();
  } catch (HttpClientErrorException | HttpServerErrorException e) {
    log.error("Hello");
    throw (e);
  } 

}

I am getting a NullPointerException because responseEntity.getBody(); is being called when it shouldn't because the line above should cause an exception.

What's wrong? Thank you!