gnome-panel is invisible on startup

I just created a fresh install of Trisquel 7.0 (Belenos) on a macbook pro retina (2013 model) using an EFI boot usb (https://trisquel.info/en/forum/conversion-macbook-pro), and selecting the encrypted home directory option.
Unrelated - the first login doesn't work, since gnome requires $HOME access that can only be gained by switching to a terminal (Ctrl-Alt-F1) to run ecryptfs-mount-private. Also, installing rEFInd from the OSX side was needed to get boot selection to work completely.

At the lightdm login screen, there was a black top-bar with wifi settings, clock, and restart menus. (I added a thinkpenguin wifi adapter).

When login finally works, neither a top nor a bottom bar shows, but Alt-F1 does produce the pop-up menu. The issue is completely reproducible, as I have never gotten the panel to appear. A list of related threads are below. I have listed attempted solutions, but they don't work. I'll try fiddling with compiz next.

Even if this is an upstream bug, it could make the system unusable for a novice, so I would recommend switching to a different default window manager for new installs!

Related threads (no suggested fixes work):

https://trisquel.info/en/forum/gnome-panel-lost
https://trisquel.info/en/forum/no-gnome-panel
$ gnome-panel --replace & # didn't work
https://trisquel.info/es/forum/task-bar-not-apearing
$ rm -f ~/.config/dconf/user # didn't work

6.0 issue thread:
https://trisquel.info/en/issues/7703