unable to add a calendar from distant ICS

Steps to reproduce

1. in the calendar app click on "New calendar"
2. then click on "New subscription from link (read only)
3. paste this one : https://collectifpinceoreilles.com/Feeds/Dates_calendrier.ics

Note : The link above passed the icalendar.org validator with 0 errors : https://icalendar.org/validator.html?url=https://collectifpinceoreilles.com/Feeds/Dates_calendrier.ics

Expected behavior

A new calendar should appear with all the appointments listed in the .ics file

Actual behaviour

You should see an error on the top-right corner saying "An error occurred, unable to create the calendar."

In the admin / logging page I have this message : "InvalidDataException The supplied iCalendar datetime value is incorrect: 20240911T203000Z"

A new calendar is created but it is empty and never show anything, even after a week waiting to update the .ics feed.

Calendar app version

4.7.16

CalDAV-clients used

No response

Browser

Firefox 130.0

Client operating system

Kubuntu 24.04 LTS

Server operating system

Ubuntu Server 22.04.4 LTS

Web server

Apache

Database engine version

MariaDB

PHP engine version

PHP 8.2

Nextcloud version

29.0.6

Updated from an older installed version or fresh install

Updated from an older version

List of activated apps

- activity: 2.21.1
  - calendar: 4.7.16
  - cloud_federation_api: 1.12.0
  - comments: 1.19.0
  - contactsinteraction: 1.10.0
  - dav: 1.30.1
  - federatedfilesharing: 1.19.0
  - federation: 1.19.0
  - files: 2.1.1
  - files_downloadlimit: 2.0.0
  - files_pdfviewer: 2.10.0
  - files_reminders: 1.2.0
  - files_sharing: 1.21.0
  - files_trashbin: 1.19.0
  - files_versions: 1.22.0
  - firstrunwizard: 2.18.0
  - groupfolders: 17.0.3
  - logreader: 2.14.0
  - lookup_server_connector: 1.17.0
  - nextcloud_announcements: 1.18.0
  - notes: 4.10.1
  - notifications: 2.17.0
  - notify_push: 0.7.0
  - oauth2: 1.17.0
  - password_policy: 1.19.0
  - photos: 2.5.0
  - privacy: 1.13.0
  - provisioning_api: 1.19.0
  - recommendations: 2.1.0
  - related_resources: 1.4.0
  - richdocuments: 8.4.6
  - serverinfo: 1.19.0
  - settings: 1.12.0
  - sharebymail: 1.19.0
  - spreed: 19.0.8
  - support: 1.12.0
  - survey_client: 1.17.0
  - systemtags: 1.19.0
  - tasks: 0.16.1
  - text: 3.10.1
  - theming: 2.4.0
  - twofactor_backupcodes: 1.18.0
  - updatenotification: 1.19.1
  - user_status: 1.9.0
  - viewer: 2.3.0
  - weather_status: 1.9.0
  - workflowengine: 2.11.0

Nextcloud configuration

No response

Web server error log

No response

Log file

No response

Browser log

No response

Additional info

No response

Start by locating the calendar app's "New subscription from link" handling and the code that reports InvalidDataException, then reproduce the issue with the supplied ICS URL. Trace the parsing of the reported datetime value and verify that the subscription is created with its appointments populated and updated normally.