new Beta update wont get my hardcore mode to play

Hello mojang studios, so i got a newest beta update 1.21.31.05 and i thought it was a hotfix. So i play it and still got the beta program, until i played my hardcore mode it wont let me get in my world. It says "a new beta update wont work in this world" message. So i created a new world it doesnt have the Hardcore mode on it. Only the hard mode.
So i decided to wait until any updates from Mojang to see if they solve this problem. It was after the new mob update "creaking mob".