Animation for interactive keyboard in iOS 8

Question

I have a view controller loaded from xib with a table view and a text field as titleView in the navigation bar. Simple.

@interface ViewController () <UITableViewDataSource, UITableViewDelegate>
@property (nonatomic, weak) IBOutlet UITableView *tableView;
@end

@implementation ViewController
@synthesize tableView;

- (void)viewDidLoad {
    [super viewDidLoad];

    tableView.keyboardDismissMode = UIScrollViewKeyboardDismissModeInteractive;
    [tableView reloadData];

    UITextField *tf = [[UITextField alloc] initWithFrame:CGRectMake(0, 0, 320, 44)];
    self.navigationItem.titleView = tf;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    return 42;
}

- (UITableViewCell*)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    UITableViewCell *cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@""];
    cell.textLabel.text = @"test cell";
    return cell;
}

@end

I tap the text field, let the keyboard show and start to drag the table view to interact with keyboard. The problem is when I release touch while interacting and let the keyboard fully show: it goes up without animation. If I release to hide it works. Furthermore this is only in iOS 8. It works in iOS 7.

Am I missing anything?