avahi-daemon takes 100% cpu over many minutes

[Angela]

Rarely the processor locks onto avahi-deamon processes and doesn't release. This can happen when the PC is not being used. Only the high fan speed alerts me. I cannot repeat it will but it repeats itself naturally.

I find in syslog lots of withdrawing and then registering IPv6 address records

ul 16 13:47:01 angela-XPS13-9333 avahi-daemon[856]: Registering new address record for 2a02:8010:9014:1:a165:d30c:a46d:fb67 on wlp2s0.*.
Jul 16 13:47:01 angela-XPS13-9333 avahi-daemon[856]: Registering new address record for fd00::1:a165:d30c:a46d:fb67 on wlp2s0.*.
Jul 16 13:49:14 angela-XPS13-9333 avahi-daemon[856]: Withdrawing address record for 2a02:8010:9014:1:f61:d516:83f5:6f4b on wlp2s0.
Jul 16 13:49:14 angela-XPS13-9333 avahi-daemon[856]: Withdrawing address record for fdc0:9f09:7835:1:befa:c254:e399:600 on wlp2s0.
Jul 16 13:49:14 angela-XPS13-9333 avahi-daemon[856]: Withdrawing address record for fd00::1:4a28:976d:1601:df6b on wlp2s0.
Jul 16 13:49:14 angela-XPS13-9333 kernel: [21448.679978] IPv6: ipv6_create_tempaddr: retry temporary address regeneration
Jul 16 13:49:14 angela-XPS13-9333 avahi-daemon[856]: Registering new address record for fd00::1:4a28:976d:1601:df6b on wlp2s0.*.
Jul 16 13:49:14 angela-XPS13-9333 avahi-daemon[856]: Registering new address record for 2a02:8010:9014:1:f61:d516:83f5:6f4b on wlp2s0.*.
Jul 16 13:49:14 angela-XPS13-9333 avahi-daemon[856]: Registering new address record for fdc0:9f09:7835:1:befa:c254:e399:600 on wlp2s0.*.
Jul 16 13:49:16 angela-XPS13-9333 avahi-daemon[856]: Registering new address record for fdc0:9f09:7835:1:a5b6:b0b2:d3ab:cf92 on wlp2s0.*.

ProblemType: Bug
DistroRelease: Ubuntu 19.04
Package: avahi-daemon 0.7-4ubuntu5
ProcVersionSignature: Ubuntu 5.0.0-20.21-generic 5.0.8
Uname: Linux 5.0.0-20-generic x86_64
ApportVersion: 2.20.10-0ubuntu27.1
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Tue Jul 16 13:36:05 2019
InstallationDate: Installed on 2019-05-08 (68 days ago)
InstallationMedia: Ubuntu 19.04 "Disco Dingo" - Release amd64 (20190416)
ProcEnviron:
 LANGUAGE=en_GB:en
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
SourcePackage: avahi
UpgradeStatus: No upgrade log present (probably fresh install)

[Angela (angela-slaney)]

18th July repeated 100% CPU use for over 5 minutes. Eventually cleared.