Structure block does not save passengers in vehicles

when saving a structure with a vehicle (boat, minecart) using the structure block, with save entities turned on, passengers in the vehicle do not get saved along with the structure and other entities that do getsaved, they are excluded. passengers in vehicle are forgotten. when the saved structure is loaded using another structure block, vehicles are empty.

here is a video showcasing this bug: https://drive.google.com/file/d/1_GLku-177pt6813QhhVIZ6lwGaxhnkyQ/view?usp=drive_link 

Reproduction:

1. use the structure block to save a structure containing a vehicle with a passenger, make sure include entities is on.

2. load the saved  structure.

Expected result:

structure loads with the vehicles and the passengers inside them

Observed result:

structure loads along with the vehicle, but the vehicle is devoid of passengers