I am running a vanilla server. I have a repeating command block that summons falling blocks using this command : execute at @e[type=item_frame,tag=barrier] run summon falling_block ~ ~-0.5 ~ {BlockState:{Name:"barrier"}} so that players can't rotate and take items from item frames with the tag "barrier". I had the chunks with those items frames forceloaded. Everything went fine. When the chunks were removed from forceloading and were unloaded, though, the falling blocks accumulated rather than despawning/"dying". So the command : execute if entity @e[type=falling_block] returned ~67.800 entities that caused arround 400 skipped ticks per second and probably increased RAM usage. I realised I had this bug since 1.11.2 or so.