When a user is notified that a message has been placed on their talk page on Wiki A, and the message is marked as read while on Wiki B, that notification is completely removed from the notification history that is visible on Wiki B. The histories should be combined so that there is a single list of historical notifications for all wikis.
@Pine, thank you and please confirm that the following steps describe the issue correctly:
- a message has been placed on a user talk page on Wiki A
- the user sees and marks the notification as read on Wiki B and, if there are no other unread notifications from Wiki A, then
- the notification disappears from the Notification panel
- Special:Notifications page (on Wiki B) does not show any messages from Wiki A - because they have been read.
Another interesting scenario:
- Have one unread notification from Wiki A.
- On Wiki B open Special:Notifications page and you'll see under Wiki A label all notifications from wiki A - read and unread
- still on Wiki B, open the Notification panel and mark the only unread notification from Wiki A as read.
- still on Wiki B, reload the Special:Notifications page and there will be no more notifications from Wiki A