Mark All Old - No Effect on "New Records" Count

I've noticed that, when I occasionally use "Mark All Old" on a group, it doesn't update the "New Records" count for the group to 0. This originally made me think that Mark All Old was having no effect whatsoever, but when I load the group, it appears to have correctly marked the posts as old, despite still showing a New Record count in the group list. Is this behavior intentional? If so, is there a setting I could toggle to change the behavior?