wajig.py crashed with PermissionError in finish_log(): [Errno 13] Permission denied: '/home/username/.wajig/hostname/Log'

I ran "wajig purgeremoved" without sudo, I was prompted for my admin password but error message was displayed after password entered:

Traceback (most recent call last):
  File "/usr/share/wajig/wajig.py", line 1087, in <module>
    main()
  File "/usr/share/wajig/wajig.py", line 1083, in main
    result.func(result)
  File "/usr/share/wajig/commands.py", line 704, in purgeremoved
    root=True, log=True)
  File "/usr/share/wajig/perform.py", line 99, in execute
    util.finish_log(temp)
  File "/usr/share/wajig/util.py", line 510, in finish_log
    lf = open(log_file, "a")
PermissionError: [Errno 13] Permission denied: '/home/paul/.wajig/N1642x/Log'

The owner of the log file is root so presumably wajig unable to write to this file.

ProblemType: Crash
DistroRelease: Ubuntu 18.04
Package: wajig 2.18.1
ProcVersionSignature: Ubuntu 4.13.0-17.20-generic 4.13.8
Uname: Linux 4.13.0-17-generic x86_64
ApportVersion: 2.20.8-0ubuntu3
Architecture: amd64
CurrentDesktop: GNOME
Date: Tue Dec 12 23:41:17 2017
ExecutablePath: /usr/share/wajig/wajig.py
InstallationDate: Installed on 2017-11-07 (35 days ago)
InstallationMedia: Ubuntu 17.10 "Artful Aardvark" - Release amd64 (20171018)
InterpreterPath: /usr/bin/python3.6
PackageArchitecture: all
ProcCmdline: /usr/bin/python3 /usr/share/wajig/wajig.py purgeremoved
Python3Details: /usr/bin/python3.6, Python 3.6.4rc1, python3-minimal, 3.6.3-0ubuntu2
PythonArgs: ['/usr/share/wajig/wajig.py', 'purgeremoved']
PythonDetails: /usr/bin/python2.7, Python 2.7.14+, python-minimal, 2.7.14-2ubuntu1
SourcePackage: wajig
Title: wajig.py crashed with PermissionError in finish_log(): [Errno 13] Permission denied: '/home/username/.wajig/hostname/Log'
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo