SUMMARY When shutting down the PC, an internal HDD has the power abruptly cut before it can spin down. STEPS TO REPRODUCE 1. Shut down the PC OBSERVED RESULT HDD gets power cut before it stops spinning. This is audible - it sounds exactly like an external HDD being unplugged while it's running. EXPECTED RESULT HDD spins down gradually before losing power ADDITIONAL INFORMATION Started happening a few weeks ago. Not sure what the root cause is.
This sounds like a local configuration issue. I would suggest asking for help on the distro forums. It is quite unlikely that KDE software is the root cause of this.