At around level Y 11 of the overworld, dirt blocks seem to still exist in the game after breaking, although they appear to be gone. This does not seem to happen at the surface level. In addition, their hitbox is still there, however very glitchy. My player seems to jitter around when it collides with the ghost block. As far as I'm aware, this does not happen to stone blocks.

The only way to make the dirt blocks reappear is by either interacting with them via a hoe, or by placing down another block in their position.

This does not happen with all of them, only about 2 in 5 blocks do this.

Something strange is that after pausing the game and going back to the surface, I cannot reproduce this glitch. I still thought it would be a good idea to post this just in case it is an actual glitch and not a one off occurrence.