I believe the notification did not get sent out for the first PR until a comment was posted on it (the PR was opened 2 days ago).
I think the top commenter on this thread (Rob) may not realize his comment is the one that is triggering the first wave of notifications, based on his choice of sound effect.
I think the top commenter on this thread (Rob) may not realize his comment is the one that is triggering the first wave of notifications, based on his choice of sound effect.