Auto upload full: no new assets found

Expected behaviour

All photos of the iOS photo library should be uploaded

Actual behaviour

On an fully reset iPhone with 15K photos synchronised from OSX Photos on it and a newly set up Nextcloud iOS App the auto upload full function does not load any photo into the cloud.
An entry is logged to the log file (log level 2):
Automatic upload, no new assets found [Auto upload full]

Steps to reproduce

1. Autoupload from a phone
2. reset the phone (fully, data and settings)
3. move the old photos from the Photos folder in the Nextcloud to another folder in the same Nextcloud.
4. synchronize the photos from MacOS (directly - not from iCloud)
5. setup the Nextcloud iOS app to point to your cloud
6. Trigger Auto upload full function

Reasoning or why should it be changed/implemented?

There should be a documented way to re-upload images with the Auto upload full function without deleting all old images from the Nextcloud (Former (and moved) upload has some images in it, which are no more present on the phone now).

iOS version

14.4

App version

3.3.1.1

Server configuration

{
    "instanceid": "***REMOVED SENSITIVE VALUE***",
    "passwordsalt": "***REMOVED SENSITIVE VALUE***",
    "secret": "***REMOVED SENSITIVE VALUE***",
    "trusted_domains": [
        "cloud.britzke.berlin"
    ],
    "datadirectory": "***REMOVED SENSITIVE VALUE***",
    "dbtype": "mysql",
    "version": "20.0.8.1",
    "overwrite.cli.url": "https:\/\/cloud.britzke.berlin",
    "dbname": "***REMOVED SENSITIVE VALUE***",
    "dbhost": "***REMOVED SENSITIVE VALUE***",
    "dbport": "",
    "dbtableprefix": "oc_",
    "dbuser": "***REMOVED SENSITIVE VALUE***",
    "dbpassword": "***REMOVED SENSITIVE VALUE***",
    "installed": true,
    "maintenance": false,
    "mail_from_address": "***REMOVED SENSITIVE VALUE***",
    "mail_smtpmode": "smtp",
    "mail_sendmailmode": "smtp",
    "mail_domain": "***REMOVED SENSITIVE VALUE***",
    "mail_smtpauthtype": "LOGIN",
    "mail_smtpauth": 1,
    "mail_smtphost": "***REMOVED SENSITIVE VALUE***",
    "mail_smtpport": "25",
    "theme": "",
    "loglevel": 0,
    "mail_smtpname": "***REMOVED SENSITIVE VALUE***",
    "mail_smtppassword": "***REMOVED SENSITIVE VALUE***",
    "updater.release.channel": "stable",
    "mysql.utf8mb4": true,
    "mail_smtpsecure": "tls",
    "memcache.distributed": "\\OC\\Memcache\\Redis",
    "memcache.locking": "\\OC\\Memcache\\Redis",
    "redis": {
        "host": "***REMOVED SENSITIVE VALUE***",
        "port": 6379
    },
    "app_install_overwrite": [
        "files_ebookreader"
    ],
    "enable_previews": true,
    "enabledPreviewProviders": [
        "OC\\Preview\\Image",
        "OC\\Preview\\Movie",
        "OC\\Preview\\TXT"
    ]
}

Operating system:
Ubuntu 20.10

Web server:
nginx
Database:
mariadb
PHP version:
7.4
Nextcloud version: (see Nextcloud admin page)
20.0.8

Start by reproducing the Auto upload full flow described in the issue, focusing on how the iOS photo library is compared with existing cloud uploads after photos are moved. Trace the Auto upload full entry point and the source of the “no new assets found” log. Done means the stated re-upload scenario works or the supported limitation and workaround are documented.