An arrow / trident inside of a block stores the properties of that block. However, it doesn't update when the properties of the block changes. An example would be that if you light up a redstone lamp after an arrow has been shot inside it, the arrow's Properties tag in the inBlockState tag will still be set to lit:"false".

Steps to reproduce

• Shoot an arrow into an unlit redstone lamp and run the following command:

  /data get entity @e[type=arrow,limit=1]

• Light up the redstone lamp and run the same command.
  ->The inBlockState tag will still be set to lit:"false" in both cases