Brought to my attention in the closely-related MC-248709.

The bug

Minecarts which display a custom block store information associated with that block in a field named "CustomDisplayTile". The term "tile" is a term which has long since been deprecated; as such, it still being used in the modern game is an issue, and causes unnecessary confusion.

How to fix

This should be renamed to something along the lines of "CustomDisplayBlock" to eliminate this term.