App update notification, yet no update button #4725

Steps to reproduce

1. NC notifies me that "action is required", so log into NC
2. Click on notification bell, it says an update for Two Factor U2F to version 1.3.1 is available.
3. Clicking on it takes me to Active Apps. Scroll down. "Two Factor U2F" is there, but only the deactivate button, no update button.

Expected behaviour

Well, I'd like to update the app ...

Actual behaviour

... but can't

Additional information

I then tried to force the current version by deactivating, deleting, and reinstalling/activating the app. Result was, that instead of version 1.3.0 which I had before, I now have 1.2.0 ... and no update button.

Server configuration

OS: debian 8, up-to-date
Web server: Apache 2.4
Database: mySQL 5.5
PHP version: 5.6
Nextcloud version: 11.0.3, updated from an older Nextcloud
Where did you install Nextcloud from: NC updater app
Signing status: "No errors have been found."

List of activated apps:
Enabled:

• activity: 2.4.1
• apporder: 0.3.3
• audioplayer: 1.5.1
• bookmarks: 0.9.1
• calendar: 1.5.2
• comments: 1.1.0
• contacts: 1.5.3
• dav: 1.1.1
• direct_menu: 0.10.1
• federatedfilesharing: 1.1.1
• federation: 1.1.1
• files: 1.6.1
• files_pdfviewer: 1.0.1
• files_sharing: 1.1.1
• files_texteditor: 2.2
• files_trashbin: 1.1.0
• files_versions: 1.4.0
• files_videoplayer: 1.0.0
• gallery: 16.0.0
• keeweb: 0.3.1
• logreader: 2.0.0
• lookup_server_connector: 1.0.0
• mail: 0.6.4
• notifications: 1.0.1
• ownbackup: 17.3.0
• ownpad: 0.5.7
• password_policy: 1.1.0
• provisioning_api: 1.1.0
• serverinfo: 1.1.1
• sharebymail: 1.0.1
• spreed: 1.2.0
• systemtags: 1.1.3
• tasks: 0.9.5
• theming: 1.1.1
• twofactor_backupcodes: 1.0.0
• twofactor_totp: 1.1.0
• twofactor_u2f: 1.2.0
• updatenotification: 1.1.1
• workflowengine: 1.1.1
  Disabled:
• admin_audit
• encryption
• external
• files_accesscontrol
• files_automatedtagging
• files_external
• files_retention
• firstrunwizard
• nextcloud_announcements
• survey_client
• templateeditor
• user_external
• user_ldap
• user_saml

Nextcloud configuration:
{
"system": {
"instanceid": "REMOVED SENSITIVE VALUE",
"trashbin_retention_obligation": "auto,90",
"versions_retention_obligation": "90,auto",
"memcache.local": "\OC\Memcache\APCu",
"memcache.locking": "\OC\Memcache\Redis",
"filelocking.enabled": "true",
"redis": {
"host": "localhost",
"port": 6379,
"timeout": 0
},
"passwordsalt": "REMOVED SENSITIVE VALUE",
"secret": "REMOVED SENSITIVE VALUE",
"trusted_domains": [
"mydomain.de"
],
"datadirectory": "REMOVED SENSITIVE VALUE",
"overwrite.cli.url": "https://mydomain.de/cloud",
"dbtype": "mysql",
"version": "11.0.3.2",
"dbname": "REMOVED SENSITIVE VALUE",
"dbhost": "localhost",
"dbport": "",
"dbtableprefix": "oc_",
"dbuser": "REMOVED SENSITIVE VALUE",
"dbpassword": "REMOVED SENSITIVE VALUE",
"logtimezone": "Europe/Berlin",
"installed": true,
"mail_from_address": "REMOVED SENSITIVE VALUE",
"mail_smtpmode": "php",
"mail_domain": "mydomain.de",
"defaultapp": "calendar",
"maintenance": false,
"loglevel": 2,
"theme": "",
"updater.release.channel": "stable"
}
}

Are you using external storage: no
Are you using encryption: no
Are you using an external user-backend: no

Client configuration

Browser: Firefox 53.0
Operating system: Linux Mint 18.1

Logs when loading the active apps page

Web server error log

"PROPFIND /cloud/remote.php/dav/files/myuser/ HTTP/1.1" 207 4791 "-" "Mozilla/5.0 (Linux) mirall/2.3.1 (Nextcloud)"

Nextcloud log (data/nextcloud.log)

(nothing)

Browser log

(did not collect this since it cannot be a client issue)