AppleWatch circle progress (or radial arc progress) with images error

I'm developing an app for Apple Watch using WatchKit and I need to implement a circular progress while recording audio, similar to Apple demos.

I don't know if WatchKit includes something to do it by default so I have created my own images (13 for 12 seconds [209 KB in total]) that I change with a timer.

This is my source code:

Button action to start/stop recording

- (IBAction)recordAction {
   NSLogPageSize();
   NSLog(@"Recording...");

   if (!isRecording) {
      NSLog(@"Start!");
      isRecording = YES;

      _timerStop = [NSTimer scheduledTimerWithTimeInterval:12.0
                                                  target:self
                                                selector:@selector(timerDone)
                                                userInfo:nil
                                                 repeats:NO];

      _timerProgress = [NSTimer scheduledTimerWithTimeInterval:1.0
                                                      target:self
                                                    selector:@selector(progressChange)
                                                    userInfo:nil
                                                     repeats:YES];
   } else {
       NSLog(@"Stop :(");
       [self timerDone];
   }

}

Action when timer is finished or if tap again on the button

-(void) timerDone{
   NSLog(@"timerDone");
   [_timerProgress invalidate];
   _timerProgress = nil;
   [recordButtonBackground setBackgroundImageNamed:[NSString stringWithFormat:@"ic_playing_elipse_12_%d", 12]];
   counter = 0;
   isRecording = NO;
 }

Method to change progress

- (void)progressChange
{
  counter++;
   NSLog(@"%d", counter);
   NSString *image = [NSString stringWithFormat:@"ic_playing_elipse_12_%d", counter];
   [recordButtonBackground setBackgroundImageNamed:image];
   NSLog(image);
}

This is a gif showing the bug. It starts to show but change the image randomly until it gets a pair of seconds. (Note: I have already checked that the first images have the right progress)