So it might not be anything to worry about. The issue could be anything from poor grounding and cable management to something like a thermostat switch flicking on and off...I've only played 2 CDs and 1 SACD so far. Both CDs glitched once, but when I played them again they played the "problem tracks" correctly...
Just to confirm... Are you using the Oppos dedicated 'HDMI Audio' output to your AVR. And if-so, is the HDMI lead okay?
If you're connecting from your Oppo through your AVR to your TV are the HDMI leads the new spec 'Premium' certified type (like the one that came with your Oppo)?