Did Call feature change in iOS 8.4?

I have an app that lets users dial a call. Basically it has number input that user enters and then it dials the number using this code.

        if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPhone) 
        {
            //its iphone
            NSString *tmpStr1 = [NSString stringWithFormat:@"tel://%@", labelStr.text];
            NSLog(@"tmpStr1: %@ ...", tmpStr1);
            [[UIApplication sharedApplication] openURL:[NSURL URLWithString:tmpStr1]];
        }
tmpStr1: tel://8003310500 ...

Recently I submitted an app update to Apple and I keep getting rejections from the Apple reviewer saying that nothing happens when the call button is pushed.

I tested this on my actual device, iPhone 6 running iOS 8 and it works just fine. My question is, did Apple change something in iOS 8.4 to disable this feature? Is there some sort of user permission needed before doing that? Unfortunately I cannot upgrade my device to iOS 8.4 at this time. (there are some personal reasons)

via Chebli Mohamed