What I expected to happen was...

Just like in 1.20.2, if you place a minecart with a different name, the name will not appear on hover

What actually happened was...

When you hover over a renamed minecart, the name will be displayed. This cannot be disabled by setting CustomNameVisible to False.

Step to reproduce

Summon minecart with this command

summon chest_minecart ~ ~ ~ {CustomNameVisible:0b,CustomName:'{"text":"Test"}'}

Then hover your cursor over the minecart and the name will appear.

I don't think it's probably a bug, but the existence of this specification greatly limits the creation of custom GUIs. Is it possible to return to the previous specifications?