Example #2 in this thread.
I wasn't noticed about this ping. I only noticed it because I checked my post. (About 20 minutes after #2 posted)
This isn't the first time that I noticed someone pinging me, without me getting a notification.
Is it a bug or perhaps caused by servers overloading. (And thus rearranging server resources to other things instead?)
You can't post in the forums yet. Play some games!