No problem. I kinda knew we were talking at cross purposes. 
I have tested the Nexus (CE20) nightlies and it’s the same. Only the 19.3 and previous (9.2.8) builds are working for me. It seems that it may be related to the newer kernel and recent Amlogic sound changes, but I’m getting good support from @vpeter and @Portisch. What makes me think that my hardware may be a contributory factor is that @Tim_Taylor has tested on his N2+ and he doesn’t have an issue. My N2+ is slightly crippled in that the USB3 ports are damaged, so I can’t use them reliably, although theoretically this should not affect HDMI sound playback. I can work around the problem, though, so it’s not a complete show-stopper for me.