On a world of mine titled 'frens' that my friends and I have been playing on for a long while, the difficulty setting is suddenly stuck on peaceful no matter which setting I choose. I wish to keep the world's achievements on, so I have no used any cheats to attempt to fix it. When the world first started, we had hostile mob spawns while not in peaceful mode. Now, switching the settings a few times does not fix it. Every rare once in a while it seems to fix itself, but then the next in-game night nothing spawns again. I'm not certain if it is the world itself or a consistent bug across the game, but nevertheless seeing it fixed would be nice.