In the Persian Wikipedia, (fa.wiki), the digits are not converted in the Echo notifications flyout. The timestamps appear with European digits (0123456789), rather than Persian (۰۱۲۳۴۵۶۷۸۹).
It does work on my local test wiki, however. I tried to investigate it with Benny a bit, and we didn't understand why does it happen on fa.wiki.
There is some discussion about it at https://gerrit.wikimedia.org/r/#/c/85711/ .