RPScreenRecorder only record the content of rootViewController

Hi, I use [RPScreenRecorder startCaptureWithHandler:completionHandler:] to record the content of view, that the view controller is presented by the rootViewController of a UINavigationController. It works normally most of the time. But sometimes, it only record the content of the rootViewController. Can you please tell me how to fix it? Thank you!

RPScreenRecorder only record the content of rootViewController
 
 
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