Syslog excerpt:

2024-09-01T15:30:01.494974-04:00 tv CRON[68297]: (root) CMD ([ -x /etc/init.d/anacron ] && if [ ! -d /run/systemd/system ]; then /usr/sbin/invoke-rc.d anacron start >/dev/null; fi)
2024-09-01T15:30:01.992630-04:00 tv plasmashell[3694]: kde.dataengine.mpris: "org.mpris.MediaPlayer2.brave.instance8658" has an invalid URL for the mpris:artUrl entry of the "Metadata" property
2024-09-01T15:30:02.009721-04:00 tv plasmashell[3694]: message repeated 2 times: [ kde.dataengine.mpris: "org.mpris.MediaPlayer2.brave.instance8658" has an invalid URL for the mpris:artUrl entry of the "Metadata" property]
2024-09-01T15:30:50.342339-04:00 tv plasmashell[3694]: kde.dataengine.mpris: "org.mpris.MediaPlayer2.brave.instance8658" has an invalid URL for the mpris:artUrl entry of the "Metadata" property
2024-09-01T15:30:58.947154-04:00 tv plasmashell[3694]: message repeated 5 times: [ kde.dataengine.mpris: "org.mpris.MediaPlayer2.brave.instance8658" has an invalid URL for the mpris:artUrl entry of the "Metadata" property]
2024-09-01T15:31:11.224717-04:00 tv plasmashell[3694]: error creating screencast "Could not find window id {d7a8b4bc-a359-4f44-b54e-90577a6efb29}"
2024-09-01T15:31:27.375139-04:00 tv plasmashell[11000]: qt.qpa.wayland: Wayland does not support QWindow::requestActivate()
2024-09-01T15:31:39.260499-04:00 tv plasmashell[11000]: kf.config.core: Created a KConfigGroup on an inaccessible config location "/mnt/pool/new/.directory" "Desktop Entry"
2024-09-01T15:31:48.874415-04:00 tv plasmashell[11000]: kf.kio.workers.file: copy() QUrl("file:///home/jk/tmp/44813__doobit__jetpropdown1.wav") to QUrl("file:///home/jk/pool/Archives/ringtones/44813__doobit__jetpropdown1.wav") mode= 436
2024-09-01T15:31:48.904165-04:00 tv plasmashell[11000]: kf.kio.workers.file: the file doesn't have any xattr
2024-09-01T15:31:48.906012-04:00 tv plasmashell[11000]: kf.kio.workers.file: copy() QUrl("file:///home/jk/tmp/476526__janosch-jr__hdd-startup-shutdown.wav") to QUrl("file:///home/jk/pool/Archives/ringtones/476526__janosch-jr__hdd-startup-shutdown.wav") mode= 436
2024-09-01T15:31:48.914252-04:00 tv plasmashell[11000]: kf.kio.workers.file: the file doesn't have any xattr
=== Start of repeated block
2024-09-01T15:31:48.925175-04:00 tv plasmashell[3694]: kf.coreaddons: Failed to open "/home/jk/tmp/476526__janosch-jr__hdd-startup-shutdown.wav" No such file or directory
2024-09-01T15:31:48.925293-04:00 tv plasmashell[3694]: QDBusConnection: error: could not send message to service "org.freedesktop.portal.Documents" path "/org/freedesktop/portal/documents" interface "org.freedesktop.portal.FileTransfer" member "AddFiles": Marshalling failed: Invalid file descriptor passed in arguments
2024-09-01T15:31:48.925327-04:00 tv plasmashell[3694]: kf.coreaddons: Some files could not be exported.  QDBusError("org.freedesktop.DBus.Error.Failed", "Marshalling failed: Invalid file descriptor passed in arguments")
2024-09-01T15:31:48.926009-04:00 tv plasmashell[3694]: kf.coreaddons: Failed to open "/home/jk/tmp/476526__janosch-jr__hdd-startup-shutdown.wav" No such file or directory
==== End of repeated block

SUMMARY

Presumably happens whenever plasma (?file dialog / dolphin ?) notices that a file was moved / deleted.
This file was deleted (? by the user in terminal ?)

plasmashell repeatedly generates above error message to rsyslog approximately 500,000 times per minute until the partition is full.
- I have _multiple_ 30GB syslog files from this ?warning? getting logged on a desktop machine.

Naturally logging stops until logrotate frees up space and security logs are unreliable from this point onwards.
Once logrotate does free up space, the issue quickly repeats and logging is toast for another week (assuming default logrotate config)


STEPS TO REPRODUCE
Open a ?dialog / dolphin? that displays files 
Go delete one of those files in a terminal window
Observe that nothing seems amiss
Check that your syslog is filling with garbage warning messages

OBSERVED RESULT
The logged in user didn't notice any problem except the system was sluggish
The admin noticed a 35GB syslog

EXPECTED RESULT
Log it once? - this seems like a minor (or needless) warning.
Display something to the user? 
Stop attempting ... whatever this is attempting.

SOFTWARE/OS VERSIONS
Operating System: Kubuntu 24.04
KDE Plasma Version: 5.27.11
KDE Frameworks Version: 5.115.0
Qt Version: 5.15.13
Kernel Version: 6.8.0-41-generic (64-bit)
Graphics Platform: Wayland
Processors: 12 × AMD Ryzen 5 5600G with Radeon Graphics
Memory: 45.0 GiB of RAM
Graphics Processor: AMD Radeon Graphics

ADDITIONAL INFORMATION
Full log partitions are a serious problem!
You won't have _any_ logs until logrotate happens, which is a week with default settings!