BACKGROUND
I have a laptop and sometimes plug it into an external screen, making a multi-screen setup with one Panel per screen. On the first screen, I have a System Tray that was put there when I installed Plasma, which has a Battery and Brightness plasmoid contained within it. On the second screen, I have an independent Battery and Brightness plasmoid on the right end of the Panel.

STEPS TO REPRODUCE
1. Have yourself a setup like the one described above.
2. Open one of the Battery and Brightness plasmoids; tick 'Manually block sleep and screen locking'.
3. Open the other Battery and Brightness plasmoid.

OBSERVED RESULT
The checkbox for 'Manually block sleep and screen locking' is not ticked.

EXPECTED RESULT
The checkbox should be ticked—that is, the two plasmoids should be synced.

SOFTWARE/OS VERSIONS
Linux kernel: 6.4.10-zen2-1-zen
KDE Plasma Version: 5.27.7
KDE Frameworks Version: 5.108.0
Qt Version: 5.15.10

ADDITIONAL IMPORTANT INFORMATION
Most importantly, when I inhibit screen locking from my secondary screen and then unplug it, the inhibition remains active and I can't turn it off using the plasmoid on my laptop screen--yes, I tried. The only way to turn it off again is to plug in the external monitor and use the plasmoid on the secondary screen, where the check box is still ticked. 

Also, whether screen locking is inhibited or not seems to be a matter of A OR B, i.e. if one checkbox or the other or both are ticked.