package libswscale-ffmpeg3:amd64 7:2.8.15-0ubuntu0.16.04.1 failed to install/upgrade: package libswscale-ffmpeg3:amd64 is already installed and configured

[Gilles]

installation error

ProblemType: Package
DistroRelease: Ubuntu 16.04
Package: libswscale-ffmpeg3:amd64 7:2.8.15-0ubuntu0.16.04.1
ProcVersionSignature: Ubuntu 4.15.0-33.36~16.04.1-generic 4.15.18
Uname: Linux 4.15.0-33-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.18
AptdaemonVersion: 1.1.1+bzr982-0ubuntu14
Architecture: amd64
Date: Fri Aug 24 21:54:41 2018
Dependencies:
 gcc-6-base 6.0.1-0ubuntu1
 libavutil-ffmpeg54 7:2.8.15-0ubuntu0.16.04.1
 libc6 2.23-0ubuntu10
 libgcc1 1:6.0.1-0ubuntu1
DuplicateSignature:
 package:libswscale-ffmpeg3:amd64:7:2.8.15-0ubuntu0.16.04.1
 Processing triggers for systemd (229-4ubuntu21.2) ...
 dpkg: error processing package libavutil-ffmpeg54:amd64 (--configure):
  package libavutil-ffmpeg54:amd64 is already installed and configured
ErrorMessage: package libswscale-ffmpeg3:amd64 is already installed and configured
InstallationDate: Installed on 2018-03-16 (163 days ago)
InstallationMedia: Ubuntu 16.04.2 LTS "Xenial Xerus" - Release amd64 (20170215.2)
RelatedPackageVersions:
 dpkg 1.18.4ubuntu1.4
 apt 1.2.27
SourcePackage: dpkg
Title: package libswscale-ffmpeg3:amd64 7:2.8.15-0ubuntu0.16.04.1 failed to install/upgrade: package libswscale-ffmpeg3:amd64 is already installed and configured
UpgradeStatus: No upgrade log present (probably fresh install)