ALAssetsGroup numberOfAssets返回0并在iPhone上使用照片库进行升级

I have an app that displays a list of photo albums to the user so they can select photos inside them and upload them to a server. That's all good and solid, but one person who upgraded their Mac and iPhoto library to Photos has reported that when they now use the app, some of their photo albums on their iPhone and iPad say "0 photos" when these albums worked before the upgrade.I have an app that displays a list of photo alb