[Bug]: Office files are corrupted/emptied after some time

⚠️ This issue respects the following points: ⚠️

• This is a bug, not a question or a configuration/webserver/proxy issue.
• This issue is not already reported on Github OR Nextcloud Community Forum (I've searched it).
• Nextcloud Server is up to date. See Maintenance and Release Schedule for supported versions.
• I agree to follow Nextcloud's Code of Conduct.

Bug description

I use Collabora Online server on the same box as Nextcloud to edit libre calc ods files and it works great I can edit a file on web and then on mobile phone.
But some times I come back to the file and it is empty, I check versions and they exist but they are all also empty no matter what revision I open.
This happened twice with different versions of Nextcloud, I lost hours of work :( I will have to make a copy manually and not open it using Nextcloud Office.

Steps to reproduce

1. Create Calc file (ods)
2. Edit on desktop browser
3. Edit on mobile phone
4. After some time open on desktop web and it is empty
5. Open on mobile phone it is empty
6. Check revision history all versions are empty (you can see it from their sizes)

Expected behavior

If some device corrupts the file it should at least not corrupt all the versions

Installation method

Other Community project

Nextcloud Server version

27

Operating system

Debian/Ubuntu

PHP engine version

PHP 8.2

Web server

Nginx

Database engine version

PostgreSQL

Is this bug present after an update or on a fresh install?

None

Are you using the Nextcloud Server Encryption module?

None

What user-backends are you using?

• Default user-backend (database)
• LDAP/ Active Directory
• SSO - SAML
• Other

Configuration report

{
    "system": {
        "datadirectory": "***REMOVED SENSITIVE VALUE***",
        "log_type": "syslog",
        "logfile": "\/var\/snap\/nextcloud\/common\/log\/nextcloud.log",
        "apps_paths": [
            {
                "path": "\/snap\/nextcloud\/current\/nextcloud\/apps",
                "url": "\/apps",
                "writable": false
            },
            {
                "path": "\/var\/snap\/nextcloud\/current\/extra-apps",
                "url": "\/extra-apps",
                "writable": true
            }
        ],
        "passwordsalt": "***REMOVED SENSITIVE VALUE***",
        "secret": "***REMOVED SENSITIVE VALUE***",
        "trusted_domains": [
            "localhost",
            "192.168.1.***",
            "nextcloud.***.syncloud.it"
        ],
        "dbtype": "pgsql",
        "version": "27.1.3.2",
        "overwrite.cli.url": "http:\/\/localhost",
        "dbname": "***REMOVED SENSITIVE VALUE***",
        "dbhost": "***REMOVED SENSITIVE VALUE***",
        "dbport": "",
        "dbtableprefix": "oc_",
        "dbuser": "***REMOVED SENSITIVE VALUE***",
        "dbpassword": "***REMOVED SENSITIVE VALUE***",
        "installed": true,
        "ldapIgnoreNamingRules": false,
        "ldapProviderFactory": "OCA\\User_LDAP\\LDAPProviderFactory",
        "memcache.local": "\\OC\\Memcache\\APCu",
        "loglevel": "2",
        "mail_smtpmode": "smtp",
        "mail_smtphost": "***REMOVED SENSITIVE VALUE***",
        "instanceid": "***REMOVED SENSITIVE VALUE***",
        "maintenance": false,
        "trusted_proxies": "***REMOVED SENSITIVE VALUE***",
        "default_phone_region": "GB",
        "mail_domain": "***REMOVED SENSITIVE VALUE***",
        "mail_sendmailmode": "smtp",
        "mail_from_address": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpauth": false,
        "check_data_directory_permissions": false
    }
}

List of activated Apps

Enabled:
  - activity: 2.19.0
  - circles: 27.0.1
  - cloud_federation_api: 1.10.0
  - comments: 1.17.0
  - contactsinteraction: 1.8.0
  - dashboard: 7.7.0
  - dav: 1.27.0
  - federatedfilesharing: 1.17.0
  - federation: 1.17.0
  - files: 1.22.0
  - files_pdfviewer: 2.8.0
  - files_reminders: 1.0.0
  - files_rightclick: 1.6.0
  - files_sharing: 1.19.0
  - files_trashbin: 1.17.0
  - files_versions: 1.20.0
  - firstrunwizard: 2.16.0
  - logreader: 2.12.0
  - lookup_server_connector: 1.15.0
  - music: 1.9.1
  - nextcloud_announcements: 1.16.0
  - notifications: 2.15.0
  - oauth2: 1.15.1
  - password_policy: 1.17.0
  - photos: 2.3.0
  - privacy: 1.11.0
  - provisioning_api: 1.17.0
  - recommendations: 1.6.0
  - related_resources: 1.2.0
  - richdocuments: 8.2.2
  - serverinfo: 1.17.0
  - settings: 1.9.0
  - sharebymail: 1.17.0
  - spreed: 17.1.2
  - support: 1.10.0
  - survey_client: 1.15.0
  - systemtags: 1.17.0
  - text: 3.8.0
  - theming: 2.2.0
  - twofactor_backupcodes: 1.16.0
  - user_ldap: 1.17.0
  - user_status: 1.7.0
  - viewer: 2.1.0
  - weather_status: 1.7.0
  - workflowengine: 2.9.0
Disabled:
  - admin_audit: 1.17.0
  - bruteforcesettings: 2.7.0
  - encryption: 2.15.0
  - files_external: 1.19.0
  - maps: 1.1.0 (installed 1.1.0)
  - suspicious_login: 5.0.0
  - twofactor_totp: 9.0.0

Nextcloud Signing status

No errors have been found.

Nextcloud Logs

No response

Additional info

No response

No source file, test, or entry point is identified, and the report includes no logs. Start by reproducing the ODS workflow with Collabora Online across desktop and mobile, then inspect the richdocuments integration, file versions, and server logs when the file becomes empty. Done means identifying the corruption path and preventing the current file and all revisions from being emptied.