Create URL Bookmark for a security-scoped URL

Hi,

I'm using UIDocumentBrowserViewController to browse the files. From the controller, I get the URL of the selected file.

Let's assume that I browse outside my app iCloud container, eg. I go to the 'iCloud Drive/Preview' and select a file located there I cannot access it.

Happens those are not regular files, those are alias files (URL Bookmarks). The bookmarks created by the Preview.app on macOS (10.13.1).

.                                   
..                                  
.00872934-B442-4252-90E6-71DF662D63D0.alias
.0137F126-9988-49F6-BD4E-EB07F434FE81.alias
.0794E1B9-36A4-4181-B41A-629864D9C8E4.alias
.0835FFAA-C6B1-44B7-B263-9B3D091DF85E.alias
.092CC36B-657B-47E1-829C-741AD19BF80E.alias
.0F2518EF-EB0D-42CE-BEFA-DCD309B4BE6E.alias
.1358DBE1-9B48-461A-956F-8C651656D955.alias
.178FF63B-4260-438F-92D3-4C9C8AE4F050.alias
.17FAE9F2-BE54-4143-952B-10A03018DD1B.alias
.19610591-C1A3-4403-B765-DCB7CB59532A.alias
.1EAECE6A-56E1-4367-A0EF-5A5A2521B35A.alias

In my case, the bookmark file points to another directory (that is an iCloud Drive directory):

.00872934-B442-4252-90E6-71DF662D63D0.alias -> file:///private/var/mobile/Library/Mobile%20Documents/com~apple~CloudDocs/Desktop/file.pdf

Since I know that I selected a bookmark file, I try to resolve the bookmark and access the destination file "Desktop/file.pds". To do so I have to as for the security-scoped access, like this:

selectedFileURL.startAccessingSecurityScopedResource() // true

then I want to ask for the access to the parent directory

selectedFileURL.deletingLastPathComponent?.startAccessingSecurityScopedResource() // false

but in that case, the access is not granted. It is not always the case though. For the application iCloud container directory, the access is granted.

Question:

1. Is this expected behavior?