No, it started at the end of last year and I made a thread about this, with only the computer-and-devices tag, last 20th december, so it remained buried in the Lounge. I’m almost sure that it was already with 11.0.0, as I did the update earlier in the month from 10.5.20.
Yep, this sums it up quite accurately, I think. As a sidenote, after coming back from work, I powered up my system and launched Cubase with still 128 samples as latency, for more tests concerning the issue. Guess what ? Everything was working, this time : no need to use the Reset button. Go figure…