Implementing PHBackgroundResourceUploadExtension

Hi,

I am trying to implement a PHBackgroundResourceUploadExtension to upload backup media files to an external cloud service based on these docs: https://developer.apple.com/documentation/PhotoKit/uploading-asset-resources-in-the-background#Acknowledge-completed-jobs

Creating jobs and actual uploading is working as expected, but the problem I have is in the acknowledgeCompletedJobs() function.

When trying to access a job's resource, the resource is nil and thus has empty assetLocalIdentifier and originalFilename.

Did anybody successfully implement this extension or knows, why this would happen? Because the resource of an acknowledgable job is empty, I can not match it back to my processed assets.