[JAVA/Spring] Mongo lastModified not updated


I have two small save and update functions :

public MyClass saveMyClass(MyClass myClass) {
    return myClassRepository.save(new MyClassModel(myClass));

public MyClass updateMyClass(MyClass myClass)
throws MyException {
    var query = new Query();

    var update = new Update();
    update.set("data", myClass.getData());

    return Optional
            mongoOperations.findAndModify(query, update, MyClassModel.class))

MyClassModel has 4 fields (id, data, createdDate and lastModifiedDate)

When I save myClass, the 4 fields are created :

id = mongoId,
data = array(String),
createdDate = currentDate,
lastModifiedDate = currentDate

However when I update the data of myClass, I noticed that the lastModifiedDate is not updated.

NB: I have enabled Mongo Auditing in my configuration.
NB2: The update is called with transactional annotation.