Chest boat placed on 3 hoppers only puts items in 1

I placed a chest boat on top of three hoppers and put items in it with another hopper

What I expected to happen was:{}

Each hopper would receive 1/3 of the items.

What actually happened was...:

One hopper got all the items.

Steps to Reproduce:
1. Put a chest boat on 3 hoppers. (I did it in a V shape)
2. Put items in the chest boat.
3. They all go in one hopper.

Video: https://drive.google.com/file/d/1-xZaggvXOlFDKSCnh-Ft5yLGGh_lC9PT/view?usp=drive_link

The hoppers are in a V shape pointing inwards, not sure if that matters