[Bug]: "Create" is displayed on a file with custom sharing permissions despite no such option is available

⚠️ 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

"Create" is displayed on a file with custom sharing permissions despite no such option is available there when adding someone by mail address.

Steps to reproduce

1. Open share menu for a file which has no shares yet. In example Documents/Example.md in the root of a fresh installation and user.
2. Enter a mail address to share the file with and confirm by hitting return.
3. The permissions selection appears. Click on "Custom permissions".
4. "Read, create, edit, delete" are shown below the "Custom permissions" heading.
5. The custom permissions checkboxes further below only offer "read", "edit" and "delete" with the "read" being selected and disabled.
6. Deselecting "edit" and "delete" leaves "read" and "create".

Expected behavior

1. The "create" is not displayed because it not even is an option here.

Nextcloud Server version

30

Operating system

Other

PHP engine version

PHP 8.2

Web server

Other

Database engine version

SQlite

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

Fresh Nextcloud Server install

Are you using the Nextcloud Server Encryption module?

Encryption is Disabled

What user-backends are you using?

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

Configuration report

{
    "system": {
        "htaccess.RewriteBase": "\/",
        "memcache.local": "\\OC\\Memcache\\APCu",
        "apps_paths": [
            {
                "path": "\/var\/www\/html\/apps",
                "url": "\/apps",
                "writable": false
            },
            {
                "path": "\/var\/www\/html\/custom_apps",
                "url": "\/custom_apps",
                "writable": true
            }
        ],
        "upgrade.disable-web": true,
        "passwordsalt": "***REMOVED SENSITIVE VALUE***",
        "secret": "***REMOVED SENSITIVE VALUE***",
        "trusted_domains": [
            "localhost"
        ],
        "datadirectory": "***REMOVED SENSITIVE VALUE***",
        "dbtype": "sqlite3",
        "version": "30.0.5.1",
        "overwrite.cli.url": "http:\/\/localhost",
        "dbname": "***REMOVED SENSITIVE VALUE***",
        "installed": true,
        "instanceid": "***REMOVED SENSITIVE VALUE***"
    }
}

List of activated Apps

Enabled:
  - activity: 3.0.0
  - app_api: 4.0.5
  - bruteforcesettings: 3.0.0
  - circles: 30.0.0
  - cloud_federation_api: 1.13.0
  - comments: 1.20.1
  - contactsinteraction: 1.11.0
  - dashboard: 7.10.0
  - dav: 1.31.1
  - federatedfilesharing: 1.20.0
  - federation: 1.20.0
  - files: 2.2.0
  - files_downloadlimit: 3.0.0
  - files_pdfviewer: 3.0.0
  - files_reminders: 1.3.0
  - files_sharing: 1.22.0
  - files_trashbin: 1.20.1
  - files_versions: 1.23.0
  - firstrunwizard: 3.0.0
  - logreader: 3.0.0
  - lookup_server_connector: 1.18.0
  - nextcloud_announcements: 2.0.0
  - notifications: 3.0.0
  - oauth2: 1.18.1
  - password_policy: 2.0.0
  - photos: 3.0.2
  - privacy: 2.0.0
  - provisioning_api: 1.20.0
  - recommendations: 3.0.0
  - related_resources: 1.5.0
  - serverinfo: 2.0.0
  - settings: 1.13.0
  - sharebymail: 1.20.0
  - support: 2.0.0
  - survey_client: 2.0.0
  - systemtags: 1.20.0
  - text: 4.1.0
  - theming: 2.5.0
  - twofactor_backupcodes: 1.19.0
  - updatenotification: 1.20.0
  - user_status: 1.10.0
  - viewer: 3.0.0
  - weather_status: 1.10.0
  - webhook_listeners: 1.1.0-dev
  - workflowengine: 2.12.0
Disabled:
  - admin_audit: 1.20.0
  - encryption: 2.18.0
  - files_external: 1.22.0
  - suspicious_login: 8.0.0
  - twofactor_nextcloud_notification: 4.0.0
  - twofactor_totp: 12.0.0-dev
  - user_ldap: 1.21.0

Nextcloud Signing status

No errors have been found.

Nextcloud Logs

None available.

Additional info

Interestingly, after a pull for the latest patch release the custom permissions offer only "read", "edit" and "delete". No more "share" as in the screenshot.

You can quickly spin up the community maintained Nextcloud Docker image with:

docker run \                                
    --rm \          
    --publish 8080:80 \
    --env SQLITE_DATABASE=nextcloud.sqlite \
    --env NEXTCLOUD_ADMIN_USER=admin \
    --env NEXTCLOUD_ADMIN_PASSWORD=admin \
    nextcloud

Start in the file-sharing custom permissions UI by reproducing the steps with the provided Nextcloud Docker command and a fresh install. Trace how the permission summary is rendered when sharing by email, then verify that the summary matches the available read, edit, and delete checkboxes and no longer shows Create.