^{Update from EVGENSYPERPRO}
Issue Summary:
Some mobs have too big a hitbox and are visually too big to ride in a boat/minecart. This causes an access issue (cannot be broken/get on the boat) to the minecart/boat, and also creates a visual problem as the mobs goes out of the boat/minecart.

Issue only for minecart:

• Guardian
• Turtle

Issue for both boat and minecart:

• Spider
• Hoglin
• Zoglin
• Ravager
• Slime (third size)
• Magma Cube (third size)
• Elder Guardian
• Ghast
• Iron Golem (MCPE-67223)
• Sniffer
• Camel
• Polar Bear
• Mule/Donkey/Horse

Mob that should be able to interact in boat/minecart :

• Panda (Boat and Minecart)
• Mule/Donkey/Horse (Interact in Minecart only)
• Turtle (MCPE-65719) (Boat only)
• Iron Golem (MCPE-67223) (Interact in Minecart only)

Steps to reproduce:

1. Place the boat/minecart.
2. Pick the mob that have been listed above.

Observed results:
Certain large mobs can get into the boat/minecart.
Cannot interact with boat/minecart with large mob inside.

Expected results:
Certain large mobs cannot get into the boat/minecart.
Can be interact in boat/minecart with large mob inside.

Note:
Baby mobs that from the larger variants can grow inisde boat/minecart and become bigger inside boat/minecart.This shouldn't be happen because their hitbox will be larger inside the boat/minecart then you will be unable to interact and have some visual glitch.