Distortion using Node 2i as streamer with Denafrips Pontus Dac

Hi all, has anyone had trouble with distortion when coupling a Node 2i streamer with a Denafrips Pontus Dac? 
I have tried using an optical, coax and usb connection from my iMac and after about a half hour to an hour I get distortion from both left and right speakers. 
On Alvin Chee’s recommendation I turned off the “Audio Clock Trim in the audio setting of the Node 2i but I still get the same distortion. 
I did have success being able to stream cd music from an Oppo CD player using an optical cable. 
Has anyone experienced similar problems? Any luck getting it resolved? I’ve only had the Pontus for a few weeks. Any suggestions would be helpful. 
I am thinking about trying another Node 2i to hear if I have the same problems. 
Bill