SUMMARY
When moving a file from ext4 to NTFS filesystem, millions (figuratively or literally, depending on your operation speed) of lines of errors are flooded into the systemd journal, at a rate of ~10000 lines/second. The NTFS system is mounted with NTFS-3G. I haven't tested with other filesystems. It looks like KCoreAddons is experiencing an infinite loop.

STEPS TO REPRODUCE
1. Make sure you have at least one ext4 filesystem and one NTFS filesystem on your disk, and mount the latter with NTFS-3G through Dolphin.
2. Using Dolphin, create a file in the ext4 filesystem (e.g. `/home/huanyu/test.txt`).
3. Select it and press Ctrl+X, so the file is cut.
4. Open a new tab and navigate to the NTFS filesystem (e.g. `/run/media/huanyu/Data`).
5. Press Ctrl+V, so the file is pasted, and record the time of operation (e.g. 11:33:00).
6. Close Dolphin as quickly as possible, unless you want to see millions of lines of errors literally.
7. Open a terminal and run `journalctl --since 11:33:00`.

OBSERVED RESULT
See the error messages below.

EXPECTED RESULT
This should not happen.

SOFTWARE/OS VERSIONS
Operating System: Arch Linux 
KDE Plasma Version: 6.1.3
KDE Frameworks Version: 6.4.0
Qt Version: 6.7.2
Kernel Version: 6.9.10-arch1-1 (64-bit)
Graphics Platform: Wayland
Processors: 16 × Intel® Core™ i7-10875H CPU @ 2.30GHz
Memory: 15.5 GiB of RAM
Graphics Processor: Mesa Intel® UHD Graphics
Manufacturer: LENOVO
Product Name: 82AX
System Version: Lenovo Legion Y7000P2020H

ADDITIONAL INFORMATION

Error Messages:
7月 22 11:33:01 huanyu-Lenovo-Legion-Y7000P2020H dolphin[3814]: kf.kio.workers.file: copy() QUrl("file:///home/huanyu/test.txt") to QUrl("file:///run/media/huanyu/Data/test.txt") mode= 420
7月 22 11:33:01 huanyu-Lenovo-Legion-Y7000P2020H plasmashell[2742]: kf.coreaddons: Failed to open "/home/huanyu/test.txt" 没有那个文件或目录
7月 22 11:33:01 huanyu-Lenovo-Legion-Y7000P2020H plasmashell[2742]: qt.dbus.integration: 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
7月 22 11:33:01 huanyu-Lenovo-Legion-Y7000P2020H plasmashell[2742]: kf.coreaddons: Some files could not be exported.  QDBusError("org.freedesktop.DBus.Error.Failed", "Marshalling failed: Invalid file descriptor passed in arguments")
7月 22 11:33:01 huanyu-Lenovo-Legion-Y7000P2020H plasmashell[2742]: kf.coreaddons: Failed to open "/home/huanyu/test.txt" 没有那个文件或目录
7月 22 11:33:01 huanyu-Lenovo-Legion-Y7000P2020H plasmashell[2742]: qt.dbus.integration: 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
7月 22 11:33:01 huanyu-Lenovo-Legion-Y7000P2020H plasmashell[2742]: kf.coreaddons: Some files could not be exported.  QDBusError("org.freedesktop.DBus.Error.Failed", "Marshalling failed: Invalid file descriptor passed in arguments")
7月 22 11:33:01 huanyu-Lenovo-Legion-Y7000P2020H plasmashell[2742]: kf.coreaddons: Failed to open "/home/huanyu/test.txt" 没有那个文件或目录
7月 22 11:33:01 huanyu-Lenovo-Legion-Y7000P2020H plasmashell[2742]: qt.dbus.integration: 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
7月 22 11:33:01 huanyu-Lenovo-Legion-Y7000P2020H plasmashell[2742]: kf.coreaddons: Some files could not be exported.  QDBusError("org.freedesktop.DBus.Error.Failed", "Marshalling failed: Invalid file descriptor passed in arguments")
... (repeated millions of times)

"没有那个文件或目录" means "The file or directory does not exist".