[WorldGuard] Owners set by plugin are not persistent

Hello,

Basically what I'm trying to do is to set owners of existing WG region.

Code:

public boolean setWGOwner(Player p, String name, Location loc) {
        ProtectedRegion rg = this.getWGRegion(name, loc);
        if(rg != null) {
            DefaultDomain list = new DefaultDomain();
            list.addPlayer(p.getName());
           
            rg.setOwners(list);
            rg.setMembers(list);
           
            return true;
        }
        return false;
    }

This seems to work flawlessly, but when the servers restarts, the changes are gone. No idea why though.

Thanks in advance