Realm Trigger match on nested array update

MongoDB Atlas Atlas Triggers & Functions
11

When I do :

realm.write(() => {
         person.cars.push(mycar);
        }
});

I receive a document with the index of the element that has been updated like

\"updateDescription\":{\"updatedFields\":{\"cars.1\":\"65f38ef80c055732995868c3\"}

However if I use unshift to add an element at the first position instead of using push (that add the element at the last position)

realm.write(() => {
         person.cars.unshift(mycar);
        }
});

the event that i receive does not contain the index part and become :

\"updateDescription\":{\"updatedFields\":{\"cars\":\"65f38ef80c055732995868c3\"}

For my use case using unshift instead of push fixed my issue

And my match expression is :
{“updateDescription.updatedFields.cars”:{“$exists”:true}}