I have never used notification, so I may be the last person to ask. The way I understand it is that the quick reply box at the bottom of the page will not affect notification you have activated previously in the thread, and that if you want to be sure you get notification, use the Advanced Editor and check the notifications box and don't use Quick Reply.
A small number of notification emails bounce because some users have free email boxes that go over quota. So the only time I deal with notification is to delete the bounces. Then I put the users in a category called "Bad Email Address" which disables their notification and newsletter to prevent the problem from recurring.
If you are in the Bad Email Address pool, notification would be disabled, not intermittent. The list is here:
http://forum.bonsaitalk.com/showgroups.php?s=
Regards,
Matt
I don't know what you mean when