MacOS Screen Saver Start After Field can not be Modified

I have this weirdest problem for MacOS BigSur version 11.1. I want to change the screen saver "Start after:" parameter to 1 minute. But every time I quit and reopen the System Preferences I see it defaults back to 20 Minutes as in the picture below. (It is like the 1990's jokes of forgetting to "save" before leaving the window.) I have a suspicion about a zombie profile can be causing this because the computer used to be managed by an MDM profile of a company that I worked for, for a while. But after my project is finished, we removed all profiles. (My suspicion is, still there may be something left that prevents modifying such System Preferences data.) I don't want to reinstall the whole system only for this silly problem, but still it is extremely annoying considering every time I leave my computer in the wild, when I come back I find it as vulnerable as a gazelle roaming in lions territory. That's why any comments / suggestions are welcome. PS: Following command, even though it does not give error, can not modify the value either:

sudo defaults -currentHost write com.apple.screensaver idleTime -int 60