@painter24 the "left channel drop" happened to me once while switching the DSD up conversion rate. I dropped the DSD rate down, then stepped it back up to 1024 and the left channel came back, but concerning none the less since you mentioned it and this problem worsened for you.
Has your new unit perform better?
Customs did a comple number on my unit, like I was shocked at how they went through everything and kinda just threw stuff back in. The dealer offered me a new unit, but he called it from the get go and asked me to look to see if the unit was "retaped on the bottom" which it was and had the obligatory customs corner punch mark underneath.