package fontconfig 2.12.6-0ubuntu2 failed to install/upgrade: triggers looping, abandoned

[Frank Humme]

error happens during update from ubuntu 16.04 to 18.04

ProblemType: Package
DistroRelease: Ubuntu 18.04
Package: fontconfig 2.12.6-0ubuntu2
ProcVersionSignature: Ubuntu 4.15.0-49.53-generic 4.15.18
Uname: Linux 4.15.0-49-generic i686
ApportVersion: 2.20.9-0ubuntu7.6
Architecture: i386
Date: Mon Apr 29 21:55:50 2019
ErrorMessage: triggers looping, abandoned
InstallationDate: Installed on 2015-09-06 (1331 days ago)
InstallationMedia: Ubuntu 14.10 "Utopic Unicorn" - Release i386 (20141022.1)
Python3Details: /usr/bin/python3.6, Python 3.6.8, python3-minimal, 3.6.7-1~18.04
PythonDetails: /usr/bin/python2.7, Python 2.7.15+, python-minimal, 2.7.15~rc1-1
RelatedPackageVersions:
 dpkg 1.19.0.5ubuntu2.1
 apt 1.6.10
SourcePackage: fontconfig
Title: package fontconfig 2.12.6-0ubuntu2 failed to install/upgrade: triggers looping, abandoned
UpgradeStatus: Upgraded to bionic on 2019-04-29 (0 days ago)