These bookmarks were pointing to directories in my iCloud Drive. These directories still exist after updating.
An example URL on iOS 14 is:
file:///private/var/mobile/Library/Mobile%20Documents/com~apple~CloudDocs/Pictures/Archive/Digital/
I create bookmarks via:
try bookmarkData(options: [], includingResourceValuesForKeys: nil, relativeTo: nil)
I resolve these bookmarks via:
try URL(resolvingBookmarkData: data, options: [], relativeTo: nil, bookmarkDataIsStale: &bookmarkDataIsStale)
Is there a specific technique required to create and resolve bookmarks after an OS upgrade?