German help does not show; message states access rights problem instead

[zapyon]

How to see the problem (on xubuntu 20.04, upgraded from 19.10):

* LibreOffice installed, including (at first) the help packages libreoffice-help-en-us, libreoffice-help-en-gb, and libreoffice-help-de, running XFCE4 in a German localization setting.
* Run LOWriter
* Click on Help -> LibreOffice Help ... (or press F1)
* Help window opens, but instead of showing the German language help, it claims there are access right problems preventing it of opening some object.

After a quick search on the web I tried purging libreoffice-help-en-us, libreoffice-help-en-gb, but this didn't end the problem.

Any suggestions?

Kind regards

Andreas

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: libreoffice-help-de 1:6.4.3-0ubuntu0.20.04.1
ProcVersionSignature: Ubuntu 5.4.0-31.35-generic 5.4.34
Uname: Linux 5.4.0-31-generic x86_64
ApportVersion: 2.20.11-0ubuntu27
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: XFCE
Date: Tue May 26 21:52:01 2020
InstallationDate: Installed on 2017-09-03 (996 days ago)
InstallationMedia: Xubuntu 17.04 "Zesty Zapus" - Release amd64 (20170412)
PackageArchitecture: all
SourcePackage: libreoffice
UpgradeStatus: Upgraded to focal on 2020-05-18 (7 days ago)