"Turn display off after" setting is not saved

I have a 16" Macbook Pro which is suffering from a [common bug that causes it to kernel panic every time it sleeps](https://mrmacintosh.com/10-15-4-update-wake-from-sleep-kernel-panic-in-16-mbpro-2019/) . Until Apple fixes this (presuming they actually do), I am trying to work around it by telling the Mac not to sleep while plugged in: However, every time I restart my computer (because I have to unplug it sometimes and then it sleeps and crashes), it forgets this setting and resets it to 5 minutes! Why isn't this setting saved? I'm using MacOS 10.15.5.