Why AVCaptureDevice.setExposureModeCustom deteriorate overexposed image on iPhone 13

I would like to take 10 photos with my iPhone with different exposure times and ISO locked at 100.0. I would like to have 5 images underexposed and 5 others overexposed. I got some images deteriorated with iPhone 13. In others iPhones it works well. I show you the result of merging images (original, 5 overexposed and 5 underexposed images):

I show you last image with the greatest exposure time value (image number 10):

As you can see, overexposed parts of image are deteriorated. In the other iPhones I have not this issue. Here is code :

var shutter_table    = [0:  1/25000.0,  1:  1/20000.0,  2:  1/16000.0,  3:  1/12500.0,
                        4:  1/10000.0,  5:  1/8000.0,   6:  1/6400.0,   7:  1/5000.0,
                        8:  1/4000.0,   9:  1/3200.0,   10: 1/2500.0,   11: 1/2000.0,
                        12: 1/1600.0,   13: 1/1000.0,   14: 1/800.0,    15: 1/640.0,
                        16: 1/500.0,    17: 1/400.0,    18: 1/320.0,    19: 1/250.0,
                        20: 1/200.0,    21: 1/160.0,    22: 1/125.0,    23: 1/100.0,
                        24: 1/80.0,     25: 1/60.0,     26: 1/50.0,     27: 1/40.0,
                        28: 1/30.0,     29: 1/25.0,     30: 1/20.0,     31: 1/15.0,
                        32: 1/13.0,     33: 1/10.0,     34: 1/8.0,      35: 1/6.0,
                        36: 1/5.0,      37: 1/4.0,      38: 1/3.0,      39: 1/2.5,
                        40: 1/2.0,      41: 1/1.6,      42: 1/1.3,      43: 1.0,
                        44: 1.3,        45: 1.6,        46: 2.0,        47: 2.5,
                        48: 3.2,        49: 4.0,        50: 5.0,        51: 6.0,
                        52: 8.0,        53: 10.0,       54: 13.0,       55: 15.0,
                        56: 20.0,       57: 25.0,       58: 30.0,       59: 40.0,
                        60: 50.0,       61: 60.0,       62: 80.0,       63: 100.0,
                        64: 120.0,      65: 140.0,      66: 160.0,      67: 180.0,  68: 200.0 ]

func set_closest_shutter(current_exposure : Double) {
    var i = 0;
    for index in 0...shutter_table.count - 1{
        if ( shutter_table[ index ]! >= current_exposure ) {
            i = index
            break
        }
        
    }
    
    current_shutter = i;
    default_shutter = i;
}

func photoOutput(_ output: AVCapturePhotoOutput, didFinishProcessingPhoto photo: AVCapturePhoto, error: Error?) {
   if let imageData = photo.fileDataRepresentation(){
        try? currentCamera?.lockForConfiguration()
        
        if pictureNumber == 0{
            set_closest_shutter(current_exposure: Float64(CMTimeGetSeconds(currentCamera!.exposureDuration)) )
            
            currentCamera?.exposureMode = .custom
            defaultWBMode = currentCamera?.whiteBalanceMode
            let gains: AVCaptureDevice.WhiteBalanceGains = currentCamera!.deviceWhiteBalanceGains
            currentCamera?.setWhiteBalanceModeLocked(with: gains, completionHandler:nil);
            
            if ( currentCamera?.isFocusModeSupported(.locked) ?? false ) {
                currentCamera?.focusMode = AVCaptureDevice.FocusMode.locked
            }
        }

        var newDurationSeconds : Double = Double(CMTimeGetSeconds(currentCamera!.exposureDuration))
        //print( "current exposure == " + String( newDurationSeconds ) )
        var newExposureTime: CMTime?
        
        if ( pictureNumber < 5 ) {
            current_shutter -= 4
            if ( current_shutter < 0 ) {
                current_shutter = 0
            }
            
            newDurationSeconds = shutter_table[ current_shutter ]!
            if ( newDurationSeconds < minDuration! ) {
                newDurationSeconds = minDuration!
            }
        }
        else {
            if ( pictureNumber == 5 ) {
                current_shutter = default_shutter;
            }
            
            current_shutter += 4
            if ( current_shutter >= shutter_table.count ){
                current_shutter = shutter_table.count - 1
            }
            newDurationSeconds = shutter_table[ current_shutter ]!
            if ( newDurationSeconds > maxDuration! ) {
                newDurationSeconds = maxDuration!
            }
        }
        newExposureTime = CMTimeMakeWithSeconds(newDurationSeconds.roundTo(toPlaces: 9), preferredTimescale: Int32(CONVERT_NANO_SECOND))
        
        //currentCamera?.activeFormat.highResolutionStillImageDimensions
        
        self.pictureNumber += 1
        if self.pictureNumber <= 10 {
            currentCamera?.setExposureModeCustom(duration: newExposureTime!, iso: ISOValue!, completionHandler: {_ in
                DispatchQueue.main.async {
                    self.photoOutput?.capturePhoto(with: AVCapturePhotoSettings(), delegate: self)
                }
            })
        }
        else {
         
        }
    }

I would like to fix this. Can you give me some steps to fix it or debug it?