kaccess repeatedly tries to install some missing Vorbis codec, spamming with notifications

Every so often, I get endless notifications:

https://unix.stackexchange.com/questions/463847/gnome-software-additional-multimedia-codecs-required-message-unclosable/615978#615978

The message is something like

'An application is requesting additional codecs'

and given how flickery the notification is in the icon bar's notification list, it's creating several such notifications per second.

Top shows 'kaccess' is very busy, and ps -axf shows

 2715 ? Sl 3:51 \_ /usr/bin/kaccess
18856 ? R 0:00 | \_ /usr/bin/gstreamer-codec-install gstreamer|1.0|kaccess|Vorbis decoder|decoder-audio/x-vorbis

killing kaccess stops the flood of notifications.

I'm guessing that kaccess is trying to alert about a notification by playing a Vorbis sound file for which is doesn't have the codec, so it's trying to load the codec, which means it needs to play a sound... for which it doesn't have the codec, etc.

1. ALL notifications should name the PROGRAM and DATA KEY+VALUE involved: kaccess is requesting additional codecs to play notification-sound /home/tim/sound/broken_audio_file.ogg'
2. Notifications should be RATE LIMITED, and/or have a 'dismiss this and identical notifications for 1 minute / 5 minutes / Forever
3. Fix whatever is causing the infinite loop, please.
4. Would be nice: have a button to open the settings to the place where the broken sound file is selected.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: plasma-desktop 4:5.12.9.1-0ubuntu0.1
ProcVersionSignature: Ubuntu 5.4.0-53.59~18.04.1-generic 5.4.65
Uname: Linux 5.4.0-53-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.20
Architecture: amd64
CurrentDesktop: KDE
Date: Tue Nov 24 11:47:42 2020
InstallationDate: Installed on 2018-06-05 (902 days ago)
InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Release amd64 (20180426)
SourcePackage: plasma-desktop
UpgradeStatus: No upgrade log present (probably fresh install)