That was actually the result of a complicated issue I’ve only heard in parts from others and managed to deduce from testing. There was something that happened with a guardian farm that caused the server to lag like hell, so the mob chunk limiter plugin was added which has a few forum posts on it. You’ll notice that many of the limits are set at 2 or 3. Most mob groups, specifically guardians, can only spawn in groups of a minimum size of 2, which means that the mob limiter plugin was actually despawning every guardian that attempted to spawn. I tested this with lazydog at my guardian farm and found that guardians were still spawning like normal, but every single guardian that attempted to spawn would be despawned by the plugin immediately. If they remove the plugin for the update or increase the caps to something that isn’t reached within ticks then the issue should disappear entirely.