Issue filtering PFUser to store it in NSMutableArray

Question

In my app, User can search other users with UISearchController implemented in a UITableViewController custom class called: "FindUsersTableViewController".

So, I load the users from parse data browser, filtering users seems to work properly as I can see it in the console, but the problem is at that point: below, this is a custom function where I store the filtered users in a NSMutableArray called "userSearchResults" (declared as property in the FindUsersTableViewController.h file):

- (void)updateFilteredContentForUsername:(NSString *)usrNameString
{
    [self.userSearchResults removeAllObjects];

// "self.allUsers" is the Array declared in the ".h" file used to get all the users with a query from the parse data browser
    for (PFUser *user in self.allUsers) {

        NSString *tempUsername = user.username;
        if ([[tempUsername lowercaseString] hasPrefix:[usrNameString lowercaseString]]) {
            [self.userSearchResults addObject:user];

// The code below works well, when I am typing on textfield of the SearchController's UISearchBar, I can see in the console all the filtered users 
            NSLog(@"%@", tempUsername);
        }
    }
// The code below shows "(null)" in the console
    NSLog(@"REMPLISSAGE: %@", self.userSearchResults);
}

Nothing stored in self.userSearchResults

Does anyone could help me to fix that issue ?