Ubiquity crashes with current lubuntu daily with GTK issues

[Draget]

Using the current daily live iso of Lubuntu (cdimage.ubuntu.com/lubuntu/daily-live/2018-0323), expert option enabled, locale set to german it crashes the installer during install.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: ubiquity 18.04.3
ProcVersionSignature: Ubuntu 4.15.0-12.13-generic 4.15.7
Uname: Linux 4.15.0-12-generic x86_64
ApportVersion: 2.20.8-0ubuntu10
Architecture: amd64
CasperVersion: 1.391
Date: Fri Mar 23 21:26:28 2018
InstallCmdLine: file=/cdrom/preseed/lubuntu.seed boot=casper only-ubiquity initrd=/casper/initrd.lz quiet splash --- priority=low debian-installer/language=de keyboard-configuration/layoutcode?=de
JournalErrors:
 Error: command ['journalctl', '-b', '--priority=err', '--lines=1000'] failed with exit code 1: Hint: You are currently not seeing messages from other users and the system.
       Users in groups 'adm', 'systemd-journal' can see all messages.
       Pass -q to turn off this notice.
 No journal files were opened due to insufficient permissions.
LiveMediaBuild: Lubuntu 18.04 LTS "Bionic Beaver" - Alpha amd64 (20180323)
ProcEnviron:
 LANGUAGE=de_DE.UTF-8
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=de_DE.UTF-8
 LC_NUMERIC=C.UTF-8
SourcePackage: ubiquity
UpgradeStatus: No upgrade log present (probably fresh install)

[Draget (dragetd)]

I can confirm that the same issue happens without the Expert option enabled and also with an english locale.