In T188590#4013192, @Aklapper wrote:

Can you please point to specific edits / revisions, not to pages without permanent links which could get changed at any time?

Also, what are your settings under Special:Preferences#mw-prefsection-echo on those two wikis?

Task Description updated, Added Permalink and on both the wikis the settings are already checked. Do you need Screenshots?

Let's see... first link now goes to https://ne.wikipedia.org/w/index.php?oldid=633720 . Going to the history at https://ne.wikipedia.org/w/index.php?title=विकिपिडिया_वार्ता:प्रमुख_लेख/प्रमुख_लेख_समन्वय_समिति&action=history and checking the last change https://ne.wikipedia.org/w/index.php?title=विकिपिडिया_वार्ता_प्रमुख_लेख/प्रमुख_लेख_समन्वय_समिति&type=revision&diff=633720&oldid=632328 I do not see any ping or mention.
Can you please clarify / point to specific edits/revisions when you were pinged/mentioned and did not receive a notification?

In the diff, you can see {{प्रवन्धक जानकारी}}, which pings not only me but also other admins of the project (newiki) but my account didn't received any notification while other admins able to receive the notification.
The source of {{प्रवन्धक जानकारी}} can be found here.

@Tulsi_Bhagat I looked into the examples that you listed in this ticket. Your last example - here seems to be formatted incorrectly. According to https://www.mediawiki.org/wiki/Template:Reply_to#Multiple_recipients, there must be a signature and no more than five recipients should be mentioned.

I looked in the database for mention notifications for @Tulsi_Bhagat on newiki, and I found a notification for B. It was marked as read about a minute after the edit (back on February 5th).

As for A, I think the reason that one didn't send a notification is because the user has a custom signature, and those are known to cause problems sometimes, see T67910: No notification when someone mentions you on a page and their signature is in a template.

As for C and D, those edits 1) added multiple sections, and 2) did not add a signature, so Echo didn't consider them to be comments. It's really frustrating that edits have to fulfill all sorts of requirements for pings to be recognized, but if that wasn't the case, every link to a user page in any context (even in a non-discussion context) would trigger a mention notification. We can't tell which pages are discussion pages and which aren't; there are many discussion pages in non-talk namespaces like the Wikipedia namespace. There's an old-ish proposal to solve this at T128535: Consider ping parser function instead of link-based mention.

Closing this task, because each of the edits reported is either an instance of an already-reported bug, or did in fact send a notification.