I noticed this behavior. Is it new?

In question Q:

user A posts an answer, then

user B posts a comment under the answer of A, then

user A posts $n$ additional comments without an @B ping, then

user B receives inbox notification of $n$ comments in question Q.

I observed this as user B. The comments of A were not edited, so that the visible comment text is the original and one can see that it never contained an @B ping, or the username of B, or quoted text or shared keywords from the comments of B, that might have generated an automatic notice.

Does the software auto-notify when the comment discussion involves only two users, or only one user other than the answerer?

• I just located the answer, I guess it is better to leave the question up, but can delete the Q and the A if that is the local procedure. – zyx Nov 21 '11 at 23:54
• It's fine to leave it here, I think. You can even accept your answer a little later! – J. M. is a poor mathematician Nov 22 '11 at 1:12
• Further info and links on how the notification system works can be found in Hendrik Vogt's answer here. – t.b. Nov 22 '11 at 1:52