Bundle tooltip does not show its interface

Steps to reproduce

1. Create a new world with the experimental feature Bundles in Creative Mode.
2. Open the inventory and get one bundle.
3. Insert some items in the bundle and watch the tooltip.

It does not show the inserted items, but shows its number. This worked correctly in 23w14a.

Code analysis

A code analysis by Captain_S0L0 can be found in this comment.