/execute as @e[type=item,nbt={Item:{id:"minecraft:minecart"}}] run data merge entity @s {Item:{tag:{CanPlaceOn:["minecraft:rail","minecraft:powered_rail","minecraft:detector_rail","minecraft:activator_rail"]}}} dosen't do anything.

So a mod by the name of tryashtar gave me this command to make it so when I break a minecart with canplaceon tags, it would drop the same minecart with canplaceon tags. It did nothing.

Please tell me what I am doing wrong or mark this as a bug.

What I am Doing:

1. Getting a minecart with the canplaceon tag for Detector Rails, Activator Rails, Powered Rails, and Regular Rails.
2. Executing the command
   /execute as @e[type=item,nbt={Item:{id:"minecraft:minecart"}}] run data merge entity @s {Item:{tag: {CanPlaceOn:["minecraft:rail","minecraft:powered_rail","minecraft:detector_rail","minecraft:activator_rail"]}

   }}
    

1. Placing down the minecart from step 1.
2. Breaking the minecart to see if the command works.
3. Seeing the minecart drop another non-tagged minecart that doesn't work.

Please fix this. Thank you.