PHObject localIdentifier not persistent between backup restores

I'm working on an app that uses photos (including Live Photos) from the users Photo Library. I'm currently storing the localIdentifier in CoreData and everything is working great. However I wanted to see if the database was persistent when the user restored from an iCloud backup. The database is intact, however all calls to fetchAssets return no items.

let options = PHFetchOptions()
options.includeAllBurstAssets = false
options.sortDescriptors = [NSSortDescriptor(key: "creationDate", ascending: false)]
options.fetchLimit = identifiers.count
        
let assetResult = PHAsset.fetchAssets(withLocalIdentifiers: identifiers, options: options)
var assetArray:[PHAsset] = []
for i in 0..    let asset = assetResult[i]
    assetArray.append(asset)
}

Am I missing something or is there a more persistent way of referencing photos in the users Photo Liibrary?

I am also concerend some people claim it can change between OS updates.