I too have this issue with the New Posts.

My best work around, is to click on Today's Posts.
Some will be darker, as in posted since I last visited the site.
Others will be lighter, indicating they were available to be read, the last time I was here.
Even the light ones will include threads I've never seen.

But at least, every post from this calendar day is found from that link.
Of course if I don't check the Software forum today, but do visit the site.
That link is useless for new posts of yesterday, which were not read.