I can dd array but I can't return it. Laravel5

I'm not sure why but I can dd an array fine but when I want to return it, it goes back as null. When I setup this if-statement, it always goes back as [1]

public function getEventInterestAttribute($event_interest){
    dd($event_interest);// //it gets printed OKAY here
    if ( ! $event_interest || empty( $event_interest ) ) { //IT PASSES THIS CONDITION and always gets returned as [1] WHY??
        $event_interest = [1];
    }
    return $event_interest;// THIS LINE NEVER GETS REACHED
}

What am I missing ?

via Chebli Mohamed