Comment 12 for bug 1741617

Note: about the original issue of the integration, there are many things around wayland still.
I heard that the Desktop Team will switch back to X11 for stability in 18.04 - didn't happen yet but should be on the way and resolve many similar issues.

On the apparmor Deny we found while testing as I mentioned I tried different setups.
Any \o/ I can now it seems:
[618537.428380] audit: type=1400 audit(1517220862.040:2924): apparmor="DENIED" operation="file_receive" namespace="root//lxd-bionic-test_<var-snap-lxd-common-lxd>" profile="/usr/sbin/libvirtd" pid=21372 comm="qemu-system-x86" family="unix" sock_type="stream" protocol=0 requested_mask="send receive" denied_mask="send receive" addr=none peer_addr=none peer="libvirt-fa4e8f6b-0211-4fb6-9e7e-93fe66133ced"

This is a crazy 16.04 - lxd-container 18.04 cloud image - 18.04 Desktop guest
                                   ^ ssh + virt-manager here
So results may vary, but that should be enough to iterate on the rule to suggest just "one" to you.
back in a bit ...