check there is anything related?
Code:
cat /var/log/messages | grep plasma
try use disk utility tools to check the health of your external drives. There might be issues with the filesystem or the drives themselves that could trigger crashes when unmounting.
Also temporarily disable desktop effects to see if they might be contributing to the issue.
Code:
kwriteconfig5 --file kwinrc --group Compositing --key Enabled false
Restart Plasmashell after disabling desktop effects
Code:
kquitapp5 plasmashell
now you have black desktop but konsole is there, run:
wait a minute and then try to reproduce issue, if everything goes fine its a problem of desktop effect...