Sinking through the world.

when i logged into my single player survival world i immediately started slowly sinking through the ground. i could move while i was sinking with wasd.
I encountered this error when i restarted my world after going afk and minimizing the game. when i came back i noticed that all my paintings and item frames were missing and also my marker on a map wouldnt move ( i believe the paintings and map thing are an unrelated issue) when i walked around. so i restarted my world to try to fix the problem. and then started sinking through the world. i restarted my world multiple times until it it didnt happen

steps to recreate bug:
1. Open inventory (to unlock the mouse)
2. Minimize the game window
3. open the game again
4. hit esc > save and exit
5. reopen world (dont restart minecraft)
6. now you should start falling through the world.