Seems like HN's "dup detector" should only check posts in the last month or so? I have the same thing, I release new features on my site and have to direct them

Seems like HN's "dup detector" should only check posts in the last month or so? I have the same thing, I release new features on my site and have to direct them to different pages when I want to announce. I guess I should start to keep some sort of blog section on my site to announce updates. But still, fixing the dup detector would be cool too.