I was playing around and using commands to summon a minecart with a name, via the “/summon minecart YourNameHere” command, and when ran it summoned a minecart, but without the name tag. I then tried using “/tp @s @e[name=YourNameHere]” to see if it was just visual, but it could not find an entity named that.
*So basically when you summon a minecart with a name, it doesn’t add the name(tag) at all. *

Steps to reproduce:
1: Create new world. Preferably a flat world as it is faster to load
2: Use the command “/summon minecart ExampleName ~~~”
3: Try and teleport to it via “/tp @s @e[name=ExampleName]

Expected result: A minecart with the name “ExampleName” is summoned, and you are able to teleport to it.

Observed result: A minecart is summoned, but with no nametag, you are also unable to teleport to it as it does not have the name specified in “[name=ExampleName]”