I've seen this glitch mentioned by other users on occasion, this bug still seems to be present in the game.

Additional details:

Smooth Lighting was turned off. Chunk rendering was set to Threaded.

I wanted to provide these details just in case.

This can happen in some general cavern environments but it's never consistent about where it might appear.

It seems more likely to happen in highly enclosed areas in where "sky" based lighting is not present.

Steps to reproduce:

This bug seems to happen the most often when a chunk is loaded in and not visited for long periods of time. I can confirm that the tunnel was being dug by myself more than a month ago and that I only returned to the spot very recently.

It very rarely can happen in general cave environments.

This is a guess, but it's a strong guess because the last time I witnessed this bug it was under very similar circumstances. It almost never seems to happen with freshly loaded chunks.