JUnit5 Test Suite doesn't test all classes from a package

I've got a Suite class as follows:

package test.suite;

import org.junit.platform.runner.JUnitPlatform;
import org.junit.platform.suite.api.SelectPackages;
import org.junit.platform.suite.api.SuiteDisplayName;
import org.junit.runner.RunWith;

@RunWith(JUnitPlatform.class)
@SuiteDisplayName("JUnit Platform Suite Demo")
@SelectPackages("test")
public class Suite {

}

And two identical test classes (they differ only by their name at the moment) in the same package called test:

package test;

import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.*;

public class testClass1 {

    @Test
    void mainA() {
        assertTrue(42==42);
    }

When I hit run on 'Suite', only testClass1 will be tested and testClass2 is left out. What am I missing?

The Suite should test classes even recursively from other subpackages in the given package if I'm not mistaken.

--EDIT: Initially I created two test classes for the same class, and the second test class gets ignored. If I add a third test class in the package, but this time for a separate class, that will get tested as expected.