OK if I have two forums A and B and I have a post lets call it "Widget" in forum A and move it to forum B the Last Post title "Widget" does get removed from forum A and now shows up under forum B's last post
IF
they are both subforums of lets say forum C then inside forum C where you see forum A and B it works as above but if your outside forum C you will see it no matter which forum A or B its in as the Last Post because it was the last post in a subforum of C
so please explain how you are seeing it work because to me it works as intended.. Or lets wait til 3.0 RC3 comes out and see where we stand then