SUMMARY
plasma-systemmonitor or ksystemstats turns on disabled nvidia graphics card (possibly, other hardware) when launches

STEPS TO REPRODUCE
1. If nvidia card is disabled (prime-select intel), when plasma-systemmonitor (or ksystemstats from terminal) launches, it turns on nvidia graphics card with optimus support (NVIDIA Corporation GP107M [GeForce GTX 1050 Ti Mobile]). In normal state, the power is off on this device. You can close plasma-systemmonitor or terminate ksystemstats (ctrl+c), but power state does not change.

2. If lspci or kinfocenter->devices->pci launched, the card turns off and this is normal behavior. Relaunch of lspci or kinfocenter->devices->pci does not behave like plasma-systemmonitor, so plasma-systemmonitor is the main suspect

3. If you launch plasma-systemmonitor or ksystemstats (getting wrong power state), close it or terminate ksystemstats (wrong power state remains) and launch again, the power state gets normal

OBSERVED RESULT
The device gets stuck in wrong power state

EXPECTED RESULT
Plasma-systemmonitor acts like kinfocenter: hardware is probed, but does not remain turned on if not needed

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Kubuntu 22.04 LTS (kernel 5.15.0-60-generic), X11
(available in About System)
KDE Plasma Version: 5.24.7
KDE Frameworks Version: 5.92.0
Qt Version: 5.15.3

ADDITIONAL INFORMATION
Powertop was used for monitoring the power state
Got this message about this bug from journald: 10.02.2023 21:38	ksystemstats	Could not retrieve information for NVidia GPU 0