Chunk keeps on dissappearing or refreshing

The chunk keeps on going away so there is no blocks there but i don't fall into the voidor it refreshes constantly to what was there a few minutes earlier

What I expected to happen was...:
Describe what you thought should happen here

What actually happened was...:
Describe what happened here

Steps to Reproduce:
1. Put a step by step guide on how to trigger the bug here
2. ...
3. ...