xlet-settings.py crashed with TypeError in set_dep_key(): argument of type 'JSONSettingsHandler' is not iterable

[rcccz]

Description: Ubuntu Bionic Beaver (development branch)
Release: 18.04

Until the other day I had German descriptions at the icons within system settings.
But now there are English ones.
I don't know, if this present bug means that.

Kind regards
rcccz

ProblemType: Crash
DistroRelease: Ubuntu 18.04
Package: cinnamon-common 3.6.7-5
ProcVersionSignature: Ubuntu 4.15.0-13.14-generic 4.15.10
Uname: Linux 4.15.0-13-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.20.9-0ubuntu2
Architecture: amd64
CrashCounter: 1
CurrentDesktop: X-Cinnamon
Date: Tue Apr 3 09:10:24 2018
ExecutablePath: /usr/share/cinnamon/cinnamon-settings/xlet-settings.py
InstallationDate: Installed on 2017-12-13 (110 days ago)
InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Alpha amd64 (20171212)
InterpreterPath: /usr/bin/python3.6
PackageArchitecture: all
ProcCmdline: /usr/bin/python3 /usr/share/cinnamon/cinnamon-settings/xlet-settings.py applet <email address hidden> 12
ProcEnviron:
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=de_DE.UTF-8
 SHELL=/bin/bash
Python3Details: /usr/bin/python3.6, Python 3.6.5rc1, python3-minimal, 3.6.4-1
PythonArgs: ['/usr/share/cinnamon/cinnamon-settings/xlet-settings.py', 'applet', '<email address hidden>', '12']
PythonDetails: /usr/bin/python2.7, Python 2.7.14+, python-minimal, 2.7.14-4
SourcePackage: cinnamon
Title: xlet-settings.py crashed with TypeError in set_dep_key(): argument of type 'JSONSettingsHandler' is not iterable
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo