Version release date picker shows a row of 'undefined' message when the user profile language is set to German, or French

Problem

While using German or French as the user language, the date picker for version releases is corrupted.

Steps to Reproduce the Problem

1. As a user, go to User Profile and change the language to German or French.
2. Go to a Scrum board.
3. Click on Releases
4. Click on the ... button for any version.
5. Click on Release.
6. Click on the date picker to choose a date.

Expected result

The release should be created

Actual result

There is an error that the date format is wrong:

Workaround

• Use other languages to select the date for the version release, as this Bug is not affecting other languages like English and Spain
• Set the release date via Project Settings > Versions page.