Same with my 950 - volume control turned up sometimes REDUCES volume and visa-versa. It also slips sometimes and the volume does not change when I turn the control. And, the transformer buzz in maddening. BUT, if I'd bought a name brand receiver 10 years ago, would it be problem-free today?
I think not.
Maybe it would be. My decade old Denon 4802R receiver has never given me a single problem. It's only the lack of new decodes and HDMI that have me looking for a new unit.