I have the ProtectedSleepers flag set in my configuration, but players are still being killed while offline. I may be reading the flag/ruleset wrong in how that is evaluated. I do have "npcs can hurt players", which is what I want for those who are online, but I want sleepers to be immune. Also, related to that, I have had a couple of issues where players are using incen ammo/fire arrows to kill sleepers. The hit itself doesn't do damage but the fireball created does. Anyway to prevent that from happening without blocking all fire damage?

ProtectedSleepers protects them from animals only. I'm not sure why it was coded that way, but I'll change it to apply to all npcs, since the description does say NPCS and not animals. it was probably added before human npcs were added to the game