Thanks for reply. But I just want to know why those mails were sent in spite of all the checkboxes were checked under Do not send notifications for post made by these authors section.
I have added new post with one of the author listed in that section which was checked.
That means no mail should be sent if that respective author has added new content. But later when I saw the settings, all the checkboxes were unchecked.
I want to know what made this changes reset?