Xubuntu - Welcome dialog booting from live not shown

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Testing 20180416 amd64
Testing on VM.

Procedure:
Boot from live CD

Observed: live cd boots directly do desktop, no welcome dialog shown.

Expected: systems boot properly and loads the installer displaying the welcome dialog

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: ubiquity 18.04.6
ProcVersionSignature: Ubuntu 4.15.0-15.16-generic 4.15.15
Uname: Linux 4.15.0-15-generic x86_64
ApportVersion: 2.20.9-0ubuntu4
Architecture: amd64
CasperVersion: 1.393
Date: Mon Apr 16 19:39:17 2018
ExecutablePath: /usr/lib/ubiquity/bin/ubiquity
InstallCmdLine: file=/cdrom/preseed/xubuntu.seed boot=casper initrd=/casper/initrd.lz quiet splash --- maybe-ubiquity
InterpreterPath: /usr/bin/python3.6
LiveMediaBuild: Xubuntu 18.04 LTS "Bionic Beaver" - Alpha amd64 (20180416)
ProcEnviron:
 TERM=unknown
 PATH=(custom, no user)
 LANG=C.UTF-8
 SHELL=/bin/bash
Python3Details: /usr/bin/python3.6, Python 3.6.5, python3-minimal, 3.6.5-2
PythonDetails: /usr/bin/python2.7, Python 2.7.14+, python-minimal, 2.7.14-4
SourcePackage: ubiquity
UpgradeStatus: No upgrade log present (probably fresh install)

[Ubuntu QA Website (ubuntuqa)]

This bug has been reported on the Ubuntu ISO testing tracker.

A list of all reports related to this bug can be found here:
http://iso.qa.ubuntu.com/qatracker/reports/bugs/1764509