And, at least for the moment, the issue has disappeared after a restart.  I'll never know what was up, but I'll keep an eye out for the issue to recur, and I hope it won't.

These sorts of bizarre and inexplicable things do happen, and very often a power cycling will fix 'em.

--

Brian - Windows 10 Pro, 64-Bit, Version 2004, Build 19041  

It’s hard waking up and realizing it’s not always black and white.

     ~ Kelley Boorn