As to the "feedback" issue….I've resolved it! I had to create a new Session, and build my routings from scratch. I THINK (not 100% sure) that the "default session" had 4 Oscillators running, wired to the analog outputs! That seems a poor choice for the default session…no?
It looks like our QC procedure for the H9000R didn't include resetting the default session, and we shipped your unit with the QC test session still loaded. Apologies for this. We are making sure that the QC procedure involves clearing the state before we send these out in future.