Yes NAD encountered teething problems with software of the M33 plus one minor hardware problem that affected a few 240 Volt units.Regarding NAD, I’d google them. The M33 has a lot of software problems. I’m not saying all people have problems, still I google it anyway. Good luck.
My M33 experienced a couple of these software problems but both were quickly resolved by NAD issuring a downloadable firmware fix kit for one and a new software release for the other.
Although one expects new products to work perfectly when released, I've given NAD the benefit of the doubt in that they were perhaps unable to do all the beta testing they'd normally do as a result of Covid.
Depite these small annoyances, the M33 is a brilliant box of tricks at a good price. Another advantage of buying these big name brands is the much greater budget they can spend of research and development as it can be distributed over sales of tens of thousands rather than perhaps hundreds of units.