i don't know if it is only for me.
Even in this xenforo forum what happens is
If i post a thread or reply to a post and after few minutes, someone replies to the thread or post.
As i am always checking the forum i will read my replies.
But only after sometime (after me reading it) i can see the alerts in top right saying someone has replied to my post.
What i am trying to tell is the alert is very much delayed. it is alerting about a reply which i have read already