Invisible sand creates forcefield

What I expected to happen was...:
I thought that i was going to just walk in my Sand Quarry.

What actually happened was...:
I got stuck and couldnt move so I tried to break the stone block in the ground, and the invisible sand that created the forcefield fell down and I could go through.

*Steps to Reproduce
Its pretty random. I dont know how to trigger it, but i can film it if that would help.