Summary: If you find a stronghold or locate one and enter and loot the stronghold you may find some floating Glow Lichen with no blocks to hold it up or it looking like glow lichen that is on a invisible block when it generated on air in the stronghold.
Steps to Reproduce:
Step 1: Load a World.
Step 2: Find a Stronghold or do /locate stronghold.
Step 3: Enter and Explore or Loot stronghold.

Observed Result: Glow Lichen can generate on air or float in stronghold making it seem or look like the Glow Lichen is on a invisible block.

Expected Result: Glow Lichen shouldn't be able to float in strongholds or generate on air.