EDIT: Ahh, pretty clever… So I noticed that when I hit back on my browser, the read threads now update, unlike before. Please disregard this question! 
…
Typically when I want to go back to the TT discussion list from within a TT thread, I usually just tap on the “Tech Talk” link in the header, i.e.
Discussion Groups > Tech Talk
It seems that the this link is now disabled for the last item in the thread chain. Was that done on purpose, or accidental? Not a big deal, but it’s the easiest way to see a refreshed list of DG topics whose updates I have not seen yet - simply hitting Back to the DG list page does not refresh the pending updates, only reloading the page does.