Symfony Valdidator does not work with nested AtLeastOneOf Constraint

In following code (condensed from a project) the validation for $constraint2 returns no error, which is not the behaviour I expect (should also return errors):

    use SymfonyComponentValidatorValidation;
    use SymfonyComponentValidatorConstraintsType;
    use SymfonyComponentValidatorConstraintsAtLeastOneOf;
    
    $config = 1; //Integer
    $constraint1 = new AtLeastOneOf([ new Type('string') ]);
    $constraint2 = new AtLeastOneOf([ new AtLeastOneOf([ new Type('string') ]) ]);
    
    $validator = Validation::createValidator();
    echo "Constraint 1: ".(count($validator->validate($config,$constraint1))).'<br>';
    echo "Constraint 2: ".(count($validator->validate($config,$constraint2))).'<br>';

Output:

Constraint 1: 1
Constraint 2: 0

The problem seems to be the nested AtLeastOneOf validator, but I do not understand why it does validate to no errors.