I have noticed that when lichens spread they have the tendency to replace blocks around them. I have had occurrences of lichens replacing obsidian over lava in caves, grass blocks and mineshaft blocks, which after a long time results in holes everywhere.

The platform above in the video has waterlogged lichens. It also seems like this is more common with flowing water but I have seen deleted blocks even on lakes. I can attach more screenshots if needed.

Had an outdated version of the mod and didn't notice the recent update