Checked this on Beta and Production (nl.wiki). In both cases Account A is getting notified about a comment from a muted user Account B.

In T285997#7231061, @Ryasmeen wrote:

Checked this on Beta and Production (nl.wiki). In both cases Account A is getting notified about a comment from a muted user Account B.

Next steps

• Editing Engineering to determine what extension the issue is in (e.g. Echo, DiscussionTools, etc.)

I can't reproduce, I don't get the notification for the comment by muted user.

(Although I can see that edit on my watchlist if I'm watching the page, and I get an email about the edit if I enabled "Email me when a page or a file on my watchlist is changed". Perhaps that's not great, but these are not part of the notifications system, and muting only applies to notifications.)

@Ryasmeen Can you please include:

• Screenshot of the notifications you received as user 1
• Screenshot of your notification preferences as user 1
• Link to the comment you posted as user 2

Also, according to https://www.mediawiki.org/wiki/Help:Notifications#mute: "You will still receive notifications if a muted user writes or participates on your user talk page".

In T285997#7241091, @matmarex wrote:

I can't reproduce, I don't get the notification for the comment by muted user.

(Although I can see that edit on my watchlist if I'm watching the page, and I get an email about the edit if I enabled "Email me when a page or a file on my watchlist is changed". Perhaps that's not great, but these are not part of the notifications system, and muting only applies to notifications.)

@Ryasmeen Can you please include:

• Screenshot of the notifications you received as user 1
• Screenshot of your notification preferences as user 1
• Link to the comment you posted as user 2

Hey @matmarex: It was on user1's sandbox talk page. Here are the screenshots:

Screenshot of the notifications you received as user 1

Screenshot of your notification preferences as user 1

Link to the comment you posted as user 2:

Thanks for the details. I've read some Echo code, and it turns out that this is a bug in Echo: it's supposed to ignore mutes only for actions on your own user talk page, but it also ignores them on the subpages of it.

The code looks like this, with a helpful comment too: (unchanged since it was added in 2017 for T150419: Allow users to restrict who can send them notifications)

						// Still notify for posts anywhere in
						// user's talk space
						$title->getRootText() === $user->getName() &&
						$title->getNamespace() === NS_USER_TALK

But all of the documentation I could find states that muting only has no effect on your own user talk page:

https://www.mediawiki.org/wiki/Help:Notifications#Muting_users

You will still receive notifications if a muted user writes or participates on your user talk page (no matter if the page uses Flow or unstructured wikitext) […]

https://meta.wikimedia.org/wiki/Community_health_initiative/User_Mute_features#Notifications_Mute

If Bananas writes a message on User_talk:Apples or participates on their Flow page, Apples will receive a notification. This is the only type of notification that Apples will receive.

As I understand, the purpose of the muting exception is to prevent users from muting everyone else and pretending that they don't see messages (the same reason why the "Talk page message" notifications can't be disabled). If that's the case, there's no reason to ignore muting on the subpages.

I filed a separate task about this: T288112. We might want to work on that (it's a trivial fix), or coordinate it, but it should not block topic subscriptions, as the bug has been there since 2017.
@Ryasmeen Please test on a different page (not a user talk or a user talk subpage).

In T285997#7259871, @matmarex wrote:

I filed a separate task about this: T288112. We might want to work on that (it's a trivial fix), or coordinate it, but it should not block topic subscriptions, as the bug has been there since 2017.
@Ryasmeen Please test on a different page (not a user talk or a user talk subpage).

@matmarex: Just did that and it works on other pages. Thanks!

We're also fixing the behavior with the subpages (see T288112), so thanks for spotting that @Ryasmeen!