Browser Tab Name not updating
This seems to relate to the new "inline" reply function (which was previously only on the responsive site), where hitting "post a reply" opens the message window at the bottom of the same page, rather than loading a new page with the text box at the top followed by the five most recent posts in reverse chronological order. If you load the thread, shut off internet access, and press "post a reply", the text box will still open normally, which shows that nothing new is being loaded, so as far as the browser is concerned, there's nothing to update.
A workaround is to select the posting character, type at least two characters into the text box, and hit "preview", which will take you to the original reverse-chronology view and display "Reply RPoL" on the tab as desired.
Obviously that's not ideal, but since it's part of the new site layout, I very much doubt that it will be changing back.