未在 iPhone 6/6+ 上触发 UIDatePicker "Value Changed" 操作

Question

I noticed an unusual behavior with the UIDatePicker.

I have a table, when I select a cell the datePicker come up.

When I change the value inside the picker, on iPhone 4s/5/5s (iOS 8) the "value changed" action is triggered as expected.

On iPhone 6/6+, the first time nothing happen (neither exception nor anything). After changing the value a second time, it works.

So, my question is simple...why on iPhone 6/6+ has this behavior?

Is it a known bug or what?

Thank you

Update:

My app is in the store since August 2012 and has always worked properly...

Here's the code

-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{
    // set the selected HH:mm date
    self.pickerView.date = [[self.fetchedResultsController objectAtIndexPath:indexPath] presence];    
    // check if our date picker is already on screen
    if (self.pickerViewView.superview == nil && self.duplicateDatePickerView.superview == nil)
    {
        [self openDatePickerView:self.pickerViewView withToolbar:self.toolBar];
    }
    self.selectedPresence = [self.fetchedResultsController objectAtIndexPath:indexPath];
}

- (IBAction)dateAction:(id)sender{
    NSIndexPath *indexPath = self.ipForDateAction;
    if(!self.selectedPresence)
        self.selectedPresence = [self.fetchedResultsController objectAtIndexPath:indexPath];
    NSDateComponents *comp = [TimeUtility hoursAndMinutesFromDate:self.pickerView.date];
    self.selectedPresence.presence = [TimeUtility date:self.selectedPresence.presence withHour:comp.hour minute:comp.minute];

    [self saveContext];
    [self timeRemainingForDate];
}

Update 2:

This strange behavior happens only setting the picker's mode to "Count Down Timer"

Answer 1

Here is a workaround for this bug. I already filed a radar to Apple and they say they are aware of this issue. This answer is provided by the user Sergio Silva that kindly answers me on the Apple developer forum:

dispatch_after(dispatch_time(DISPATCH_TIME_NOW, 0.1 * NSEC_PER_SEC), dispatch_get_main_queue(), ^{
[self.myDatePicker setCountDownDuration: xxxxxx];




 //or [self.myDatePicker setDate:xxxx animated:NO];
});