When placing chests under Glass you can open them. This doesn't work with other Full Blocks like Iron Block.
To Reproduce this Bug:
Place Glass Block
Place Chest under Glass Block
Open the Chest (Bug)
Comments 2
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I don't think that this is a bug, since the glass is considered to be a transparent block rather than a full block, so you can still open chest under them and you can't even suffocate inside glass blocks.