In Unleashed 200.15, GUI provides false feedback when toggling the "Directed MC/BC: Enable" setting. Checking or unchecking the box in the GUI updates the Directed MC/BC Threshold variable and the GUI's own visual state, but it fails to modify the underlying Directed Multicast Boolean in the system configuration.
I only discovered this after having issues with my mDNS and Matter/Thread network and digging into the settings by hand with the CLI.
Posting here not for help, but to surface the bug.