Well, I hadn’t a lot of time to play these days but I didnt have any problem after the update. I will test more carefully this evening!
EDIT: Nope, I was wrong. Still the same problem. Everithing works fine, then I relog and it stops working. I have to restart the game to fix it. I think it happens only on relog. Then ,again, even if the link between portalts is gone, thermomethers still read temperature from some block that slowly goes down from the initial reading.