Hi Gerry. Here’s output on my desktop:
jani@saegusa:~$ gsettings get com.canonical.Unity2d.Launcher hide-mode
1

Here’s output on my laptop, which is also affected:
jani@lemmikki:~$ gsettings get com.canonical.Unity2d.Launcher hide-mode
2

(I’ve changed the setting myself using dconf-editor on my desktop but not on my laptop, IIRC.)

Amusingly, it’s as if that query now triggered the issue at hand: launcher is currently stuck visible on both computers as I’m typing this. Let me try… No, unfortunately it was apparently just a coincidence: I couldn’t reproduce it with the gsettings command deliberately again after killing the stuck U2D.