I found this strange behavior while making a datapack and haven't found a related bug.

The issue:
Apparently the following workstations aren't considered neither a Block nor an Entity by the game and running "/data get block X Y Z" doesn't returns any data:

• Cartography Table
• Composter
• Fletching Table
• Cauldron
• Stonecutter
• Loom
• Smithing Table
• Grindstone

The blocks on the top work for the "/data" command, while the ones on the bottom don't.

Running "/data get block 247 56 63" on Blast Furnace returns it's data:

Running "/data get block 245 56 58" on Cartography Table DOES NOT returns it's data:

This renders the player or scripts unable to fetch these workstation's coordinates, for example.