Decoding png with CoreGraphics framework on iOS17 leads to loss of alpha channel

I used the following code to decode the image in png format into the allocated memory block *imageData.

- (void)decodeImage:(UIImage*)image 
{

    GLubyte* imageData = (GLubyte*)malloc(image.size.width * image.size.height * 4);

    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();

    CGContextRef imageContext = CGBitmapContextCreate(imageData, image.size.width, image.size.height, 8, image.size.width * 4, colorSpace, kCGImageAlphaPremultipliedLast | kCGBitmapByteOrderDefault);

    
    CGContextDrawImage(imageContext, CGRectMake(0.0, 0.0, image.size.width, image.size.height), image.CGImage);

    CGContextRelease(imageContext);

    CGColorSpaceRelease(colorSpace);
    
    int bytesPerRow = image.size.width * 4;

    //you can log [330, 150] RGBA value here, then gets wrong alpha value;

    int targetRow = 330;

    int targetCol = 150;

    u_int32_t r =  (u_int32_t)imageData[targetRow*bytesPerRow*4 + targetCol*4 + 0];
    u_int32_t g =  (u_int32_t)imageData[targetRow*bytesPerRow*4 + targetCol*4 + 1];
    u_int32_t b =  (u_int32_t)imageData[targetRow*bytesPerRow*4 + targetCol*4 + 2];
    u_int32_t a =  (u_int32_t)imageData[targetRow*bytesPerRow*4 + targetCol*4 + 3];

    free(imageData);
}

The CGBitmapInfo used is kCGImageAlphaPremultipliedLast | kCGBitmapByteOrderDefault.

The problem is that the alpha channel is lost in the decoded result:

For example, the RGBA values ​​of the target png at [row, col] = [330, 150] are R = 240, B = 125, G = 106, A = 80.

If the decoding is correct, the expected result should be R = 75, G = 39, B = 33, A = 80 with AlphaPremultiplied.

However, after decoding the png on iOS17, the result is R = 75, G = 39, B = 33, A = 255, where the alpha values ​​are all forced to 255.

Xcode Version 15.0 beta (15A5160n). iPhone14 Pro.

The png file: