Just to update on the reported issue. @alvin1118 of Vinshine Audio provided instructions to update Amanero USB firmware. That seems to resolve the issue with jumping tracks (similar issue as reported by @bt304, thanks) but I have not played long enough to conclude yet.
Regarding Sony HAP-Z1ES showing "An unsupported USB device has been connected" error message, if I turned on Terminator first and select USB input, then turn on Sony HAP, then there is no error at all. After that, with both devices already on, if I switch Terminator to other input (Amanero shuts down) and then back to USB (Amanero powers up), there error "An unsupported USB device has been connected" still shows up.