I can confirm that I've noticed this issue as well but toggling dirac on/off/on does the trick. Dirac 2.0 works for me but only on one of my computers. Not sure what the deal is there really. I had long email exchange with them but in the end I grew tired of doing their work for them.
On a different note, now after having owned the receiver for a couple of years almost I'm still happy with it. I don't have any major issues with it at all really. It would be cool if the software felt rock solid but not sure if any product has that now a days. All my previous receivers have all had hardware issues which is far more annoying. Weird noises, channel imbalances, channels changing levels or turning of completely and so on. None of that with the Arcam and I find it being a better preamp than my previous receivers by far.
Room| Treated | Sound| Front: Ino Audio i32s, Center: Ino Audio i16s, Surrounds: 6 x Ino a2, 6 x Ino a1, Subs: 6 x Ino Infra-Y|
Picture | Epson TW9300, Seymour Center Stage UF 130.4" retractable 2.35:1 |
Electronics | Arcam AVR390(Dirac Live), 3x Ncore nc400 monoblocks, Emotiva XPA-2 Gen2, EP4000, Panasonic UB700, Allo Katana + Isolator 1.2(Roon bridge/DAC), ATV 4K |