iOS Button not clickable during animation

I tested on Swift 4

 UIView.animate(withDuration: 0.8, delay: 0, options: [.repeat, .autoreverse, .allowUserInteraction], animations: {
        // Do Something
    }, completion: nil)

Try this it will help you

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
      UITouch *touch = [touches anyObject];
      CGPoint touchLocation = [touch locationInView:self.view];
      for (UIButton *button in self.arrBtn)
      {
          if ([button.layer.presentationLayer hitTest:touchLocation])
         {
        // This button was hit whilst moving - do something with it here
            [button setBackgroundColor:[UIColor cyanColor]];
             NSLog(@"Button Clicked");
             break;
         }
      }
}

From the doc

During an animation, user interactions are temporarily disabled for the views being animated. (Prior to iOS 5, user interactions are disabled for the entire application.) If you want users to be able to interact with the views, include the UIViewAnimationOptionAllowUserInteraction constant in the options parameter.

So your code should be

- (void)pulse:(float)secs continuously:(BOOL)continuously {
    [UIView animateWithDuration:secs/2 
                          delay:0.0 
                        options:UIViewAnimationOptionCurveLinear | UIViewAnimationOptionAllowUserInteraction
                     animations:^{
                         // Fade out, but not completely
                         self.alpha = 0.3;
                     }
                     completion:^(BOOL finished) { 
                         [UIView animateWithDuration:secs/2 
                                               delay:0.0 
                                             options:UIViewAnimationOptionCurveLinear | UIViewAnimationOptionAllowUserInteraction
                                          animations:^{
                                              // Fade in
                                              self.alpha = 1.0;
                                          }
                                          completion:^(BOOL finished) { 
                                              if (continuously) {
                                                  [self pulse:secs continuously:continuously];
                                              }
                                          }];
                     }];

}