Why my ios only share my own app screen, not share other app screen

Hi Carson
In fact I get a new issue. same code has different result in ipad and iphone. In iphone share screen works well, includes voice, video sharing is smooth.
In Ipad voice always stop in several seconds later; and video stops, too.
Whether I should add some code in this function?

- (void)processSampleBuffer:(CMSampleBufferRef)sampleBuffer withType:(RPSampleBufferType)sampleBufferType {
    [self.screenShareService processSampleBuffer:sampleBuffer withType:sampleBufferType];
    switch (sampleBufferType) {
        case RPSampleBufferTypeVideo:
            // Handle video sample buffer
            break;
        case RPSampleBufferTypeAudioApp:
            // Handle audio sample buffer for app audio
            break;
        case RPSampleBufferTypeAudioMic:
            // Handle audio sample buffer for mic audio
            break;
            
        default:
            break;
    }
}

I test several devices to get these results: