Villagers Disappear When I Save And Quit Or When I Am Near Them

Whenever I Save And Quit My World All The Villagers And Mods Disappear (Despawn).They Even Despawn When I Am There In The World.It Happens In Creative And Survival In My Minecraft Version 1.17.20.21 Beta.When My Villagers First Disappeared In My Village In Survival, I Brought Villagers From Another Village But They Agian Disappeared They Next Day I Started My Game.Villagers Even Disappear If I Name Tag Them.If It Is A Bug Please Fix It, If It Is A Feature Please Remove It.