Please upgrade Moment.js to version 2.6.0, which has many bug fixes and several new features. In particular, Moment.js was using an incorrect language code for Vietnamese (vn instead of vi); upgrading should fix the issue in which Hovercards were showing timestamps like “Sửa đổi lần cuối 9 days ago”.
As a side note, it needs to be easier for MediaWiki’s very thorough translators to find out that timestamps are being translated in an obscure third-party project on GitHub.
Version: unspecified
Severity: enhancement
URL: https://github.com/moment/moment/pull/1556