Correction: the edit text used the Hebrew equivalent of the {{Ping}} template:

This is the diff: https://he.wikipedia.org/w/index.php?title=%D7%A9%D7%99%D7%97%D7%AA_%D7%9E%D7%A9%D7%AA%D7%9E%D7%A9:Aviados&diff=prev&oldid=18256961

So it looks like EchoDiscussionParser::getTextSnippet() just strips all templates. I don't really understand why it works the way it does. For snippets of Flow discussions, we take the HTML version and strip it down. For wikitext discussions, we start with wikitext, strip tags, strip templates, THEN parse it, replace   with spaces, decode, strip tags AGAIN, remove { and } (why?!), then truncate.

Change 276687 had a related patch set uploaded (by Catrope):
Unconvolute DiscussionParser::getTextSnippet()

https://gerrit.wikimedia.org/r/276687

Other weird behavior in the old implementation:

• Anything wrapped in / produced by a template was stripped. As the bug report says, this includes {{ping|Username}}, and it's very unhelpful to strip these
• Including odd entities in comments (e.g. ὣ which is ὣ) caused no snippet to be shown at all
• I have reason to believe { and } got removed wherever they appeared

These apply to wikitext mentions and edit-user-talk notifications; for Flow notifications, snippet behavior is much more sane. My patch basically takes the Flow logic and applies it to wikitext notifs.

1. {{ping|Username}} produces - notice the added colon @Username:

{{FlowMention|Username}} will display @Username

{{ {{{|safesubst:}}}#time:i}} will display e.g. 06

{{CURRENTTIME}} will display e.g. 22:06

2. ὣ will be displayed as ὣ

Note: Currently, wikitext User talk pages do not display text excerpts (except when a user was mentioned).

The test case to check after the fix:

-on a wikitext User talk page create a new section with a title: ὣ

• in the body of that section Mention a user
• the mentioned user receives broken notification

The rendered section looks like - also, View changes page: http://en.wikipedia.beta.wmflabs.org/w/index.php?title=User_talk:ET60&oldid=prev&diff=326673

Change 276687 merged by jenkins-bot:
Unconvolute DiscussionParser::getTextSnippet()

https://gerrit.wikimedia.org/r/276687

Checked in betalabs - a tricky topic title e.g. ὣ in Notifications is displayed properly.