Bruce, GDM3 in Ubuntu these days actually uses Wayland by default even though the GNOME login is still X by default.
1. In the GNOME Settings app, is Sharing turned on or off?
Try switching it the other way.
2. If that doesn't work…
Does it work any better if you temporarily remove
org.gnome.SettingsDaemon.Sharing;
from
/usr/share/gnome-session/sessions/gnome.session
You may need to restart for this change to take effect.
As for LP: #1559576 does your NVIDIA computer have xserver-xorg-legacy installed?
Bruce, GDM3 in Ubuntu these days actually uses Wayland by default even though the GNOME login is still X by default.
1. In the GNOME Settings app, is Sharing turned on or off?
Try switching it the other way.
2. If that doesn't work… SettingsDaemon. Sharing; gnome-session/ sessions/ gnome.session
Does it work any better if you temporarily remove
org.gnome.
from
/usr/share/
You may need to restart for this change to take effect.
As for LP: #1559576 does your NVIDIA computer have xserver-xorg-legacy installed?