In Minecraft Java addition I found the glasses acts as a full block, which un-allows light to pass through. By placing it on the ground you can see a shadow and no light source can remove the shadow casted by the glass.

Put the summary of the bug you're having here

What I expected to happen was...:
Glass to be clear and for light to pass through it

What actually happened was...:
Glass didn't let light pass through it when place directly on the ground

Steps to Reproduce:
1. Put a step by step guide on how to trigger the bug here
2. Put multiple blocks of glass near each other on any ground
3. The blocks will form a shadow that no light can remove