AVAssetImageGenerator leaking memory

When I generate an image from a ProRes Codec asset, the instrument shows the memory leak.

If I switch the asset into H264 one, no leaking.

Here is my simple code.

let testURL = URL(fileURLWithPath: "Pat_To_Movie_file")
let asset = AVAsset(url: testURL)
let avAssetImageGenerator = AVAssetImageGenerator(asset:asset)
avAssetImageGenerator.appliesPreferredTrackTransform = true
do {            
     let cgImage = try avAssetImageGenerator.copyCGImage(at: CMTimeMake(value: 0, timescale: 1), actualTime: nil)
} catch let error as NSError {
     print(error)
}

I really appreciate all your help.

My spec is MacOS 10.15.4 and Xcode Version 11.5.

Thanks!