Glow Lichen can generate mid-air

Glow Lichen can generate mid-air with no supporting blocks attached. I found this issue in the Portal Room in a Stronghold, but I am unsure if it is limited to that.

Glow Lichen would break if I added a supporting block and then remove that new supporting block.

 

I was on a Single Biome world as Dripstone Caves

Seed Example: 755195345125533742

Co-ordinates: -2259 -20 433