Cannot extract imagePair from generated Spatial Photos

Hi I am trying to implement something simple as people can share their Spatial Photos with others (just like this post). I encountered the same issue with him, but his answer doesn't help me out here.

Briefly speaking, I am using CGImgaeSoruce to extract paired leftImage and rightImage from one fetched spatial photo

let photos = PHAsset.fetchAssets(with: .image, options: nil)
// enumerating photos ....
if asset.mediaSubtypes.contains(PHAssetMediaSubtype.spatialMedia) {
        spatialAsset = asset
}
// other code show below

I can fetch left and right images from native Spatial Photo (taken by Apple Vision Pro or iPhone 15+), but it didn't work on generated spatial photo (2D -> 3D feat in Photos).

// imageCount is 1 when it comes to generated spatial photo
let imageCount = CGImageSourceGetCount(source)

I searched over the net and someone says the generated version is having a depth image instead of left/right pair. But still I cannot extract any depth image from imageSource.

The full code below, the imagePair extraction will stop at "no groups found":

func extractPairedImage(phAsset: PHAsset, completion: @escaping (StereoImagePair?) -> Void) {
        let options = PHImageRequestOptions()
        options.isNetworkAccessAllowed = true
        options.deliveryMode = .highQualityFormat
        options.resizeMode = .none
        options.version = .original
        return PHImageManager.default().requestImageDataAndOrientation(for: phAsset, options: options) {
            imageData, _, _, _ in
            guard let imageData,
                let imageSource = CGImageSourceCreateWithData(imageData as CFData, nil)
            else {
                completion(nil)
                return
            }
            let stereoImagePair = stereoImagePair(from: imageSource)
                completion(stereoImagePair)             
            }
        }
}

 func stereoImagePair(from source: CGImageSource) -> StereoImagePair? {
            guard let properties = CGImageSourceCopyProperties(source, nil) as? [CFString: Any] else {
                return nil
            }
            let imageCount = CGImageSourceGetCount(source)
            print(String(format: "%d images found", imageCount))

            guard let groups = properties[kCGImagePropertyGroups] as? [[CFString: Any]] else {
                /// function returns here
                print("no groups found")
                return nil
            }
            guard
                let stereoGroup = groups.first(where: {
                    let groupType = $0[kCGImagePropertyGroupType] as! CFString
                    return groupType == kCGImagePropertyGroupTypeStereoPair
                })
            else {
                return nil
            }

            guard let leftIndex = stereoGroup[kCGImagePropertyGroupImageIndexLeft] as? Int,
                let rightIndex = stereoGroup[kCGImagePropertyGroupImageIndexRight] as? Int,
                let leftImage = CGImageSourceCreateImageAtIndex(source, leftIndex, nil),
                let rightImage = CGImageSourceCreateImageAtIndex(source, rightIndex, nil),
                let leftProperties = CGImageSourceCopyPropertiesAtIndex(source, leftIndex, nil),
                let rightProperties = CGImageSourceCopyPropertiesAtIndex(source, rightIndex, nil)
            else {
                return nil
            }
            return (leftImage, rightImage, self.identifier)
}

Any suggestion? Thanks visionOS 2.4