No I see it too, the most recently modified threads are marked "new" and they are still marked even after reading them. I suppose that it is meant to do that.
The markings are reset when you log out and in again; perhaps it checks what was changed since the last time you logged in, but within a maximum period so it wouldn't mark everything as "new" when you come back to the site after a week.
The markings are reset when you log out and in again; perhaps it checks what was changed since the last time you logged in, but within a maximum period so it wouldn't mark everything as "new" when you come back to the site after a week.