Thanks! I realized the one thing I hadn't done was a full power-off reboot of my home internet router. Did that, and the problem went away, apparently entirely. I seem to be getting all channels without glitches in minutes of watching, each.
I'll have to reboot the router whenever I water the cactus ...

Thanks. I checked with a voltmeter and it's putting out a solid 5V. The DUO is responding fine in every function (firmware update, etc) except digitization, so it doesn't sound like a good bet. I'll probably have to replace the whole thing. If the new unit has the same power brick, I can try it on ...

I have a CONNECT DUO, 10679D4B, purchased 2019. It's been great the whole time.
It was suddenly creating only chopped-up, barely legible, video and audio on all channels. I checked my antenna with the TV alone and was getting perfect reception. On Unix, the hdhomerun_config_gui was showing fine ...