I am already using the external dialogs, due to other issues long ago forgotten…probably having to do with shared drives ;-). This is the setting as I started this message.

Oddly enough, for S&Gs I tried switching to INTERNAL dialogs. That correctly shows the mapped network shares (after LB restart, of course). And what’s even more bizarre, when I switch back to external and restart LB, then those mapped network shares show up as expected.
Go figure.
So, um, I guess that means It’s a transitory issue?
And just so we all know I’m not totally insane, this behavior was witnessed and the fix duplicated on both a Win10 and Win11 machine.