Yes, we just used our HHN 2018 refillable cups in October. We did have issues getting them re-activated, but two different TMs told us that the specific HHN cups we had were always a problem.
On our first day, we activated them for 3 days at the kiosk in front of MiB. The machines there were closed, so we went to the Coke building to the right of MiB. When we tried them, they didn't work.
The TM there told us those cups were an issue from the start. She worked at it for about 5 minutes and had us try them. My wife's worked, but mine didn't. After another 5 minutes of cancelling then ringing it up again, it finally worked. She warned us that we would probably have the same issue each morning. And she wasn't wrong.
We also had a problem one day in the middle of the day where they randomly deactivated. A quick stop at a kiosk (where they had to call over a manager to help), and we were back up and running.
Overall, it was a minor hassle and we still felt it was worth bringing them.