blocks not save on a specific place in my singleplayer world

I updated my world from 1.16.5 to 1.17 and I have this bug which at spawn (the mushroom island) the blocks that I place or remove revert to it's original state when I log out and log in.
 
Video: https://www.reddit.com/r/Minecraft/comments/nvvmyf/blocks_not_saving_in_my_singleplayer_base_117/