double notification by email

Steps to reproduce

1. Share a file by link
2. wait for its expiration
3. receive two mail to the same topic

Expected behaviour

There should be only one mail about the same topic (also valid for other notifications in other contexts)

Actual behaviour

Two emails instead of one.

Server configuration

Operating system:
Ubuntu 20.04
Web server:
Apache/2.4.53
Database:
mysql Ver 15.1 Distrib 10.3.34-MariaDB, for debian-linux-gnu (x86_64) using readline 5.2

PHP version:
PHP 8.0.17
Nextcloud version: (see Nextcloud admin page)

Where did you install Nextcloud from:
upgraded since Owncloud 4
Signing status:

Login as admin user into your Nextcloud and access
http://example.com/index.php/settings/integrity/failed
paste the results here.

List of activated apps:

Enabled:
  - accessibility: 1.9.0
  - activity: 2.15.0
  - admin_audit: 1.13.0
  - bbb: 2.2.0
  - bookmarks: 10.3.1
  - bruteforcesettings: 2.4.0
  - calendar: 3.2.2
  - calendar_resource_management: 0.1.0-alpha2
  - circles: 23.1.1
  - cloud_federation_api: 1.6.0
  - collectives: 1.0.0
  - comments: 1.13.0
  - contacts: 4.1.0
  - contactsinteraction: 1.4.0
  - dashboard: 7.3.0
  - dav: 1.21.0
  - deck: 1.6.1
  - federatedfilesharing: 1.13.0
  - federation: 1.13.0
  - files: 1.18.0
  - files_external: 1.15.0
  - files_pdfviewer: 2.4.0
  - files_rightclick: 1.2.0
  - files_sharing: 1.15.0
  - files_trashbin: 1.13.0
  - files_versions: 1.16.0
  - files_videoplayer: 1.12.0
  - firstrunwizard: 2.12.0
  - groupfolders: 11.1.2
  - impersonate: 1.10.0
  - issuetemplate: 0.7.0
  - logreader: 2.8.0
  - lookup_server_connector: 1.11.0
  - nextcloud_announcements: 1.12.0
  - notes: 4.3.1
  - notifications: 2.11.1
  - oauth2: 1.11.0
  - password_policy: 1.13.0
  - passwords: 2022.4.20
  - photos: 1.5.0
  - polls: 3.5.4
  - previewgenerator: 4.0.0
  - privacy: 1.7.0
  - provisioning_api: 1.13.0
  - recommendations: 1.2.0
  - richdocuments: 5.0.3
  - richdocumentscode: 21.11.306
  - serverinfo: 1.13.0
  - settings: 1.5.0
  - sharebymail: 1.13.0
  - spreed: 13.0.5
  - support: 1.6.0
  - survey_client: 1.11.0
  - systemtags: 1.13.0
  - tasks: 0.14.4
  - text: 3.4.1
  - theming: 1.14.0
  - twofactor_backupcodes: 1.12.0
  - updatenotification: 1.13.0
  - user_status: 1.3.1
  - viewer: 1.7.0
  - weather_status: 1.3.0
  - workflowengine: 2.5.0
Disabled:
  - cms_pico: 1.0.18
  - encryption
  - files_fulltextsearch: 23.0.1
  - files_fulltextsearch_tesseract: 22.0.0
  - fulltextsearch: 23.0.0
  - fulltextsearch_elasticsearch: 23.0.0
  - guests: 2.2.0
  - integration_whiteboard: 0.0.14
  - user_ldap

Nextcloud configuration:

{
    "system": {
        "instanceid": "***REMOVED SENSITIVE VALUE***",
        "passwordsalt": "***REMOVED SENSITIVE VALUE***",
        "secret": "***REMOVED SENSITIVE VALUE***",
        "trusted_domains": [
            "***REMOVED SENSITIVE VALUE***",
            "***REMOVED SENSITIVE VALUE***"
        ],
        "datadirectory": "***REMOVED SENSITIVE VALUE***",
        "overwrite.cli.url": "***REMOVED SENSITIVE VALUE***",
        "dbtype": "mysql",
        "version": "23.0.4.1",
        "dbname": "***REMOVED SENSITIVE VALUE***",
        "dbhost": "***REMOVED SENSITIVE VALUE***",
        "dbtableprefix": "oc_",
        "dbuser": "***REMOVED SENSITIVE VALUE***",
        "dbpassword": "***REMOVED SENSITIVE VALUE***",
        "default_language": "de",
        "logtimezone": "Europe\/Berlin",
        "installed": true,
        "maintenance": false,
        "mail_smtpmode": "smtp",
        "mail_smtpsecure": "ssl",
        "mail_smtpauth": 1,
        "mail_smtpauthtype": "LOGIN",
        "mail_smtpport": "465",
        "mail_from_address": "***REMOVED SENSITIVE VALUE***",
        "mail_domain": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpname": "***REMOVED SENSITIVE VALUE***",
        "mail_smtppassword": "***REMOVED SENSITIVE VALUE***",
        "app.mail.server-side-cache.enabled": true,
        "preview_max_x": "2048",
        "preview_max_y": "2048",
        "jpeg_quality": "60",
        "enabledPreviewProviders": {
            "1": "OC\\Preview\\Image",
            "2": "OC\\Preview\\MarkDown",
            "3": "OC\\Preview\\MP3",
            "4": "OC\\Preview\\TXT",
            "6": "OC\\Preview\\Movie"
        },
        "enable_previews": true,
        "theme": "",
        "loglevel": 1,
        "trashbin_retention_obligation": "auto",
        "updatechecker": false,
        "mysql.utf8mb4": true,
        "htaccess.IgnoreFrontController": true,
        "htaccess.RewriteBase": "\/",
        "updater.release.channel": "stable",
        "app_install_overwrite": [
            "occweb",
            "issuetemplate"
        ],
        "memcache.local": "\\OC\\Memcache\\APCu",
        "memcache.distributed": "\\OC\\Memcache\\Redis",
        "memcache.locking": "\\OC\\Memcache\\Redis",
        "redis": {
            "host": "***REMOVED SENSITIVE VALUE***",
            "port": 0,
            "timeout": 0
        },
        "default_phone_region": "DE",
        "mail_sendmailmode": "smtp",
        "mail_smtphost": "***REMOVED SENSITIVE VALUE***",
        "updater.secret": "***REMOVED SENSITIVE VALUE***"
    }
}

Are you using an external user-backend, if yes which one: LDAP/ActiveDirectory/Webdav/...

Client configuration

Browser:

Operating system:

Logs

Nextcloud log (data/nextcloud.log)

Insert your Nextcloud log here

Browser log

Insert your browser log here, this could for example include:

a) The javascript console log
b) The network log
c) ...

No source files or tests are named. Start by reproducing the link-share expiration scenario in the Activity app and trace the email notifications it produces. Done means the same topic results in one email rather than two, including other notification contexts.