The bug
When you set CustomNameVisible to 1b for certain entities without providing a CustomName, their default name is not displayed.
How to reproduce
Use the following command
/summon Cow ~ ~ ~ {NoAI:1b,Health:0.1f,CustomNameVisible:1b}The cow has the name "Cow"
Use the following command
/summon MinecartRideable ~ ~ ~ {CustomNameVisible:1b}The name is not displayed
Linked issues
Comments 3
Why is this a bug? It makes sense as there is no other way to have for example a cow with the translated word for cow and if only the CustomNameVisible tag is set to 1b then the person who did this probably did this on purpose.
The default name is not a custom name. Making entities show their custom name should show their custom name (if they have one), not their default name. This ticket will stay resolved unless default names being displayed with CustomNameVisible turns out to be WAI. Feel free to create a ticket for that so we can find out.
Translatable nametags would be a feature request so that point is irrelevant.
The minecart has no custom name. Why should it display its regular name with CustomNameVisible? If anything, the cow displaying "Cow" is a bug.