I get these pops and clicks when the H9000 and my audio interface aren’t sync’ed. I usually hard restart the audio interface because it’s set to external sync or I reset the sync rate on the H9000 (switch from 48k to 44.1k and back). This doesn’t happen often, maybe once every couple of months. I keep my rack gear on 24/7, so, it’s bound to get out of sync occasionally.