If a block with a non generated loottable is replaced with the clone command the block turns into a barrier block. Sometimes the block is not updated client-side therefore the block looks like the original block.

Recreation:

• Place two impulse command blocks above each other
• Set the command of the lower command block to
  "setblock ~ ~2 ~ minecraft:chest{LootTable:"minecraft:blocks/acacia_button"}"
• Set the command of the upper command block to
  "clone ~ ~2 ~ ~ ~2 ~ ~ ~1 ~ replace"
• Activate only the lower command block (for example with a redstone block)
• A chest will appear on the upper command block
• Activate only the upper command block (for example with a redstone block)
• Right click the chest if it is still visible
• The chest turned into a barrier block

Demonstration video: https://imgur.com/TxtK7PN