Spring boot - maven failsafe plugin shares spring context among tests

My intention is to enhance configuration of one test among other ones. I am using @TestConfiguration inner class for that specific test. As I understand the flow of how tests are run by SpringRunner the tests are sharing spring context unless some test specify @DirtiesContext annotation. Here is one sample:

public class TestClass {

    @TestConfiguration
    static class TestConfig {
       @Bean
       @Primary
       public SomeBean testDateTimeProvider() {
          return new SomeBean();
       }
    }

    @Autowired
    private SomeBean someBean;

}

Curious think is that when I run the set of tests from my IntelliJ IDE, all test pass without problem but from maven (failsafe-plugin) I get an error because in other test, there is this bean exposed from the test above.

Am I assuming correctly, that test share same context unless some of them specifies @DirtiesContext and the problem is that when this test creates SomeBean then other tests will see also it?

By the way, I have solved this situation by removing @TestConfiguration class and importing it directly to test using @Import annotation.

Thank you very much.